US2370683A - Analytical apparatus - Google Patents

Description

, March 6, 1945. A. v. FALMA ANALYTICAL APPARATUS Filed June 17, 1940 2 Sheets-Sheet -l R MM M N 2 V 4 ma w 5 z Km m a 2.

March 6, 1945. v P 2,370,683

ANALYTICAL APPARATUS Filed June 17, 1940 2 Sheets-Sheet 2 i v I Affoz'zzey Patented Mar. 6, 1945 UNITED STATES PATENT OFFICE Application June 17, 3:21;:0. 341,054

5 Claims.

My invention relates broadly to analytical methods and apparatus and more particularly to an improved method and readily portable apparatus for effecting chemical reactions and determining qualitatively or quantitatively the contents of'a specimen under observation.

One of the objects of my invention is to provide a dry method of eil'ecting chemical reactions and determining qualitatively or quantitatively, or both, the contents of a specimen under investiga-' tion.

Another object of my invention is to provide a compact form of test package which may be conveniently used by chemists in detecting the presence of sugar in molasses sludge in the process of alcohol manufacture without the applicatio of heat.

Still another object of my invention is to provide a simplified and rapid method readily usable by individuals without the exercise of any substantial degree of skill for determining the percentage of sugar in urine and in blood to aid in estimating the amount of insulin required to prevent conditions of diabetes, acidosis and coma.

A further object of my invention is to provide a method of urinalysis which utilizes a dry, stable, non-flammable, powdered mixture instead of a solution for securing a chemical reactionwith a specimen of urine for purposes of determining the percentage of sugar in the urine.

A still further object of my invention is to provide an arrangement of compact portable kit which includes all elements required to quickly eflect a qualitative or quantitative analysis of a specimen without the necessity of a flame or a reactive solution.

Another object of my invention is to provide a construction of calibrated chart carrying indications thereon adapted to be directly compared with the results of chemical reactions between a specimen and a reactive agent for determining the percentage of sugar in the specimen under observation.

Still another object of my invention is to provide a method of urinalysis which employs a dry reagent comprising sodium hydroxide (NaOH), bismuth sub-nitrate Bi(OH)2NO3 or bismuth sub-carbonate Bi(Ol-I)2CO3 and .tartaric acid H:(C4H4Os) which is subject to reduction under the action of a drop of urine to enable comparisons to be made with respect to a color chart for determining the percentage of sugar content in the urine. g

A further object of my invention is to provide with indicia and observation apertures therethrough for comparing theindicia with the color characteristic of the reduction between a chemical reagent and a specimen for determining the percentage of constituents in the specimen.

Another object of my invention is to provide an arrangement of calibrated chart and filter paper book which permits indicia on the calibrated chart to be matched against a reduction between a chemical reagent and a specimen for determining by comparison with indicia on the chart, the percentage of constituents in the specimen.

Still another object of my invention is to provide a construction 0! indicating chart for use in comparing known characteristics between a multiplicity ofian-ioid members each carrying an arrangement of comparative chart equipped indicia thereon and observation apertures therethrough for enabling the indicia to be directly matched with a reduction process between a specimen and a reagent for determining the percentage of constituents in the specimen.

A still further object of my invention is to provide a constructionof container for receiving a reagent to be reduced by combination with a specimen in which the container is provided with a protective resilient rim.

Other and further objects of my invention reside in a method and apparatus for performing chemical analysis asset forth more fully in the specification hereinafter following by reference to the accompanying drawings, in which:

Figure 1 is a plan view showing one form of chemical analysis set embodying my invention with the cover for the set shown partially in position and the comparison chart for comparing reactions between the reagent and the specimen shown partially withdrawn from the package; Fig. 2 is a plan view of the package illustrated in Fig.;1 with the comparison chart removed and the container for the chemical reagent illustrated partiallyin section; Fig. 3 is a longitudinal section view taken on line 3-3 of Fig. 1; Fig. 4 is-a plan view of the comparison scale or chart employed in the method and apparatus of my invention; Fig. 5 is a transverse sectional view through the scale or chart shown. in Fig. 4 on line 55 of Fig. 4; Fig. 6 is an elevational view partially broken away and illustrating the structure of pipette dropping vial employed as a container for the specimen under observation and for delivering the specimen in the required droplet to the chemical reagent for effecting the reduction and observation with the use of the comparative chart; Fig. 7 is an elevational view of the container for the chemical reagent, the container being partially broken away and illustrated in section to illustrate the powdered reagent therein; Fig. 8 is a perspective view of one form of cup-like container and annular protective resilient ring thereon, which container is adapted to receive the chemical reagent and the specimen for examination with respect to the coacting indicating chart shown in Fig. 4; Fig. 9 is a view of a modified form of test set having means for effecting qualitative as well as quantitative tests; Fig. 10 is a transverse sectional view taken substantially on line ill-ill of Fig. 9; Fig. 11 is a perspective view of the form of comparative chart disposed in assembled relation with a stack of filter papers as employed in the form of test set illustrated in Figs. 9 and 10; Fig. 12 is a plan view with parts broken away and partially illustrated in section showing a further modified form of test set embodying my invention and including a comparative chart having a multiplicity of callbrated observation apertures therein adapted to be registered with a chemical deposit of reagent and specimen for determining quantitatively the percentage of constituents in the specimen according to known characteristics indicated on the calibrated comparative chart; Fig. 13 is a longitudinal sectional view taken on line l3-l3 of Fig. 12; Fig. 14 is a perspective view of the calibrated comparative chart employed in the test set shown in Figs. 12 and 13; Fig. 15 is a plan view of a further modified arrangement of test set in which the comparative chart is arranged in the form of a. multiplicity of registrable strip-like members, each carrying calibrated indicia thereon adapted to be registered with a deposit of chemical reagent and specimen on a test plate for determining the percentage of constituents in the specimen; Fig, 16

, is a longitudinal sectionalview through the test set shown in Fig. 15 on line iii-46 thereof; Fig.

17 is a transverse sectional view taken on line l'I-il of the test set; Fig. 18 is an extended plan view of the calibrated indicia used in the comparative chart provided in the test set of Figs.15, 16 and 17; Fig. 19 is a perspective view of a protective support employed for the specimen carrying plate in the set of Figs. 15-17; Fig. 20 is a perspective view of the specimen carrying plate employed in the form of my invention illustrated in Figs. 15-17; Fig. 21 is a plan view of a further modified form of test set embodying my invention and illustrating a form of specimen receiving plate having calibrated comparative markings directly mounted thereon for observation with respect to a reduction process between a chemical reagent and. the specimen under observation; Fig. 22 is a longitudinal sectional view taken on line 22-22-Qf Fig. 21; Fig. 23 is a plan view partially broken away and illustrating a. further modified form of test set employing a modified construction of cup-like container for receiving a deposit of chemical recalibrated chart.

agent and a specimen under observation for effecting a reduction which may be observed through calibrated apertures in a comparative chart associated with the test set; and Fig. 24 is a transverse sectional view taken on line 24-24 of Fig. 23.

My invention is directed to a method and apparatus for quantitatively and qualitatively determining the percentages of contents in a specimen under analysis. The presence and amount of sugar in molasses sludge in the process of alcohol manufacture, may be readily determined by the method and apparatus of my invention. For purposes of explaining my invention, I have illustrated its application to the determination of the existence of and the amount of sugar in urine. My invention provides a very rapid method for determining the existence and/or quantity of sugar in urine. By knowing the percentage of sugar both in urine and in blood, physicians can estimate the necessary amount of insulin to administer to a patient to prevent diabetes, acidosis and coma. Unlike all the standard methods used in hospitals and clinical laboratories, my method employs areagent which is a dry, stable, non-flammable, white powdered mixture and not a fluid solution as generally required. This mixture is prepared from bismuth sub-nitrate Bi(OI-I)zNO3; sodium hydroxide NaOH; and tartaric acid H2(C4H4Os) The powdered mixture is deposited in a fiat dish-like member or on a test plate or on filter paper and a drop of the specimen applied to the powder. A reaction is obtained, the color of which is proportional to the percentage of sugar in the specimen. The calibrated sugar chart of my invention is then compared with the reaction and the percentage of sugar in the specimen immediate- 1y estimated from the comparable colors on the The test requires less than fifteen seconds for completion. All standard methods heretofore known take at least four minutes and considerable apparata, i. e., test tube, clamp, gas flame (or lamp), pipette, sugar solution (reagent), water bath, matches, etc. My kit is composed of a crucible, test plate or filter paper, reagent powder, a dropper, and the sugar chart. My invention greatly reduces the cost of the sugar test as compared with the standard methods in hospitals or laboratories. The diabetic test is greatly simplified so that the layman (and children) can understand the test and perform it. The test is fool proof. One drop of undiluted urine on powdered reagent will change it to yellow indicating no sugar; or some degree of gray or black indicating positive sugar. Comparing the reduction of the reagent with the color chart, the percentage. of sugar is readily estimated. The powdered reagent is important to clinical laboratories because of its ability to react chemically with urine and change color by reduction. By using a multiple porcelain spot plate, many tests can be performed quickly and accurately. The molasses chemist can use my method to detect presence of sugar in sludge in the process of alcohol manufacture. The package containing the reagent and chart is light, compact, pocketable, safe and always ready; it can be easily placed in a purse, handbag, medicine cabinet or oifice. The powdered reagent permits the test to be made anywhere, in or out of buildings, on sea, on aircraft, ships, submarines, etc. No flame is necessary, thereby reducing fire hazard. Over 250 tests conducted on diabetic and non-diabetic urines in a clinical laboratory according to my invention showed very close checks to those done by the long cumbersome test made. The chart reading may be multiplied by a dilution factor for quantitative sugar determination. Normal constituents of urine do not affect the sodium hydroxide powdered mixture as proven by many experiments.

Referring to the drawings in more detail, reference character I designates a container or package in which all of the elements constituting the chemical analysis apparatus of my invention are mounted. The container or package I is divided into sections by means of partition members illustrated at 2 and 3. I arrange in one end of the package or container I a transversely extending strip 4 having opposite ends thereof directed toward each other as represented at 5 and slotted at 6 to engage the resilient rim I of the flat con-' tainer or dish-like member 8. The container or dish-like member is thus protected when the package is carried in a pocketbook, purse, physicians case, salesmans kit or during shipment. The dry powdered chemical reagent employed in the process of my invention is shown at 9 in container Ill sealed by screw cap II. "The specimen under observation may be placed in a vial I2 containing pipette or dropper I4. The collapsible rubber cap I5 on pipette or dropper I4 is employed to transfer a drop of the specimen from vial I2 to the powdered reagent which is placed in container or dish-like member 8. The reduction which is produced is observed through apertures in the comparative chart or scale shown at IS in Fig. 4. The comparative chart or scale l6 carries indicia thereon in the positions I have indicated at I1, I8, I9, 20 and 2|, calibrated according to the color characteristics of reductions which occur between a specimen of known characteristic and the chemical reagent. The indicia are arranged in accordance with the percentage content of the constituent which produces the color characteristic shown by the corresponding indicia. The chart is apertured at the several indicia as indicated at 22, 23, 24, 25 and 26. The entire comparative chart or scale is enclosed in a transparent covering indicated at 21 which extends Wholly over the apertures in the scale or comparative chart and protects the scale or comparative chart from contact with the specimen or chemical reagent while permitting the chart to be moved transversely over the container or dish-like member 8 to align the calibrated indicia with the reagent and specimen in the container or dish-like member 8 and to permit an optical comparison to be made between the color of the reagent after being subjected to the reduction process and the color characteristics of the indicia.

I have indicated the manner in which the chart may be enclosed within the package in Figs. 1 and 3. I also provide a length of wrapped fabric or cloth 28 in the package for use'during a test. A cover 29 is provided to close the container I with all of the elements therein. The chemical reagent employed! is a powdered mixture prepared from bismuth sub-nitrate Bi(OH)-zNOc; sodium hydroxide NaOH; and tartaric acid H2(C4H4Os). Bismuth sub-carbonate may be satisfactorily substituted for the nitrate of bismuth. My experiments also show that bismuth salts mixed with NaOH reduced sugar of diabetic urine in various degrees. The proportions of the constituents which are mixed to provide the powdered reagent are as follows:

One-tenth part by weight Bi(OH) zNOa, or

Bi(OH) zCOa.

Two parts by weight NaOH pulverized fine.

One part by weight H2(C4H40e) pulverized fine.

. In order to increase the potency of the reduction,

I may introduce the tartaric acid constituent onehalf by weight in the pulverized state and onehalf by weight in the crystalline state. The constituents are thoroughly powdered and intermixed and provide a reagent which is potent in its reduction characteristics.

; In Figs. 9-11 I have shown a test set and component parts thereof which is adaptable for quantitative analysis as well as qualitative analysis. Within the container 28 I provide compartments 29 and 30. In compartment 29 I provide a graduated pipette 3i which is accurately calibrated in subdivisions T ecc. for the purpose of dropping a predetermined amount of fluid into either of the receptacles 32, 33 or 34 in the block 35. The powdered reagent is carried in the tubular container indicated generally at 36 adapted to be housed in compartment 30. The set includes the filter paper stack or book of filter paper leaves shown generally at 31 over which there .may be superposed the. calibrated chart 38. The calibrated chart 38 carries indicia similar to chart 2! in Fig. 4. Each of the indicia are characteristically colored to accurately represent known reductions. The several indicia are indicated at 39, 40, M, 42 and 43. Each of the indicia are calibrated in percentages of known constituents and are assigned a number in the reaction scale. Each of the indicia are apertured centrally as indicated at 39a, 40a. 4Ia, 42a and 43a. The calibrated chart is covered by a glassine or Cellophane protective sheet indicated at 44 for the protection of the scale while permitting a reduction effected between the reagent and a specimen deposited on a sheet of filter paper indicated at 3'! to be observed. In proceeding with an observation, a sheet of filter paper is removed from the stack 31, the reagent and specimen deposited thereon and the comparison made by viewing the reduction through the apertures in the several indicia in the calibrated chart 38 until correspondence of color characteristics is obtained, thereby enabling a reading of both qualitative and quantitative characteristics of the specimen to be obtained. It will be observed that the scale 38 is retained by the cover 45 of the filter paper book. This permits the chart to be supported by the two portions of the cover 45 which may be bent back and manually grasped in combination with the filter book 31 to enable the scale to be moved over one of the sheets of filter paper removed from the filter book for the purpose of performing a test. The filter book fits snugly within the container 28 as shown in Fig. 10. A section of fabric or cloth 46 is mounted in the container and a cover 41 provided for the container for maintaining the component Parts of the test set in a compact unit. The filter paper book shown in Fig. 11 is a particular feature of the test set shown in Figs. 9 and 10, in that the bendable portions of the cover 45 with the filter paper stack form a handle support for moving the calibrated chart over a selected sheet of the illter paper carrying the reagent and specimen.

When using the test set of Figs. 9, 10 and 11 for qualitative and quantitative sugar analysis on urine, predetermined dilutions of the specimen must be made. Dilutions I found satisfactory were 1 in 5 (or 1 in 10) made either by using one drop of diabetic urine to four drops of tap (or distilled) water in oneof the three recesses 32, 33 or 34 of the porcelain dish or block 35. Since the pipette dropper 3| with bulb is graduated to 1 cc. and divided into ten subdivisions of 1 00., then various dilutions of diabetic urine in tap water is feasible; for example, to make a one in ten dilution of highly concentrated diabetic urine, it is only necessary to aspirate 1 6 cc; oftap water into the graduated pipette 3| and force into the left-hand recess 32 of porcelain dish or block 35; then aspirate 1% cc. diabetic urine into the graduated pipette 3| and force into the water in recess 32. Mix the solution with the empty pipette 3|. The same procedure is used for one in five dilution except that 1 6 cc. urine is forced into tic of water. Into the middle recess 33 in dish 35 the powdered mixture constituting the reagent is introduced and the reduction test conducted. The test requires the application of one drop of the diabetic urinewater mixture onto the powdered reagent. After the reduction is complete, the scale 38 is used and the percentage of sugar computed by multiplying by factor it A dilution was used, or by 10 if {a dilution was used. For example, I first test on unknown diabetic urine for the presence of sugar, depositing one drop of undiluted urine on small quantity of powdered reagent on a sheet of filter paper 31. If I find very black reduction according to the scale 38 I know the specimen contains over 1% sugar, but how much? To find out this, I make a 1 in 5 dilution as hereinbefore described and this dilution is tested in exactly the same way. It will then be found quiring substantial equipment. When the test set is used by a layman I recommend the preparation of urine sugar, water solution by using "drop method, i. e., one drop of urine to flve drops of water. For more qualified persons such as physicians, nurses, technicians, etc. I recommend measuring out portions from graduated pipette, i. e., 1% cc. urine into 1% cc. water and the computation made as hereinbefore explained. However, with both methods the results can be recorded on a percentage basis or upon a relative basis using the values'1+, 2+, 3+, or 4+, etc., and stating whether diluted or undiluted solutions are tested. When the test is repeated, day by day, a diabetic will note fluctuations from 1+ to 4+ in the method used, i. e., diluted or undiluted urine.

that the scale reading will fill in the lighter areas of the scale 38, for example, near the dark gray which reads 0.25 sugar. Then by calculation 0.25% 5=l.25% provides the result, or if a one in ten dilution was used, then sugar is present in the specimen. If the concentration of sugar in the urine sample is low enough to fall within the range of the indicator chart. i. e., between 0 and 1%, a quantitative determination is made by direct comparison with the color standards (0.12%, 0.25%, 0.50%, and 1% or over). If the concentration of sugar inthe urine sample is above 1%, a quantitative determination can be made by diluting the urine with water until the dilute solution gives a color reaction which falls within the range of the indicator chart. In the latter case the chart reading must be corrooted to represent the concentration of sugar in the original urine sample by multiplying the figure according to the degree of dilution. For example: If the urine sample gives a reading on the chart of 1% or over, nine parts of water may be added to one part of urine and the test repeated. If now the color reaction falls below 1% on the chart, the reading is corrected to represent the per cent of sugar in the original urine sample by multiplying by ten, since the diluted solution contains only ten per cent urine. By using this method I checked closely over 250 diabetic urines and found my simplified method equally satisfactory to cumbersome methods re- For clinical laboratories and physician's offlces, I recommend the use or a larger dish or block such as 35 having a large number of recesses for performing multiple sugar tests. Recesses up to twelve in a porcelain plate corresponding to block 35 may be used to great advantage in expediting a number of substantially simultaneous observations.

Figs. 12, 13 and 14 illustrate another form of apparatus embodying my invention in which the container 48 includes a compartment 49 within which the dropping vial 50 and the container for the powdered reagent indicated at 5| may be housed. In this set a plain glass slide 52 is provided having a concave central portion 51 adapted to be supported by the roldable card 54 shown more particularly in Fig. 14. The i'oldable card 54 is provided with a central white background indicated at 55 and indicia distributed along the card indicated at 56, 5'1, 53 and 59 in the symmetrical arrangement shown so that the card may be grasped in its central portion for locating the card with respect to the recessed flat slide in comparing the reduction successively with the indicia 55-59 without making it necessary for the fingers to contact and soil the color indicia areas representing the different degrees of reductions and/or to provide a surface area for comparing the reductions against the white backgrounds when the indicia are viewed through the glass slide 52. Each oi! the indicia is provided with color characteristics according to reproducing known reactions between a specimen and reagent and each provided with a scale reading and percentage constituent reading corresponding to the color characteristic. Each of the indicia is apertured as represented at 56a, 51a, 58a and m, the apertures extending through the chart for permitting the reduction between the reagent and the specimen to be observed and compared with the indicia. The dry powder reagent is deposited in the recess 53 in glass slide 52, the specimen added thereto for producing the reduction and the chart 54 moved either over or under the glass slide to match the reduction with the indicia carried by the chart in order that accurate asraeas by a member 88 which passes through aligned I eyelets in the several leaves. The leaves 62 and 88 comprise backing members which protect the individual leaf members. The leaves 63-81 each carry. indicia thereon which I have indicated at 18, 1 I, I2, 13 and 14 showing color characteristics mined. The reduction is carried on by use of the glass plate 52 having recess 83 therein. The

' plate 52 is normally mounted on the base constituted by foldable card I which provides a white background against which the color characteristics of the reduction are readily observable when selecting the desired leaf and comparing through the sight aperture therein the characteristics of the reduction with the known characteristics set forth by the indicia on the leaves.

The set of Figs. 15-20 iscom-pleted in a manner similar to the set of Figs. 12-14 with fabric or cloth 68 and a cover 8| for the container 48.

Figs. 21 and 22 illustrate a further form of my invention employing a modified arrangement of chart. The chart in this instance is formed upon a glass plate indicated at 16 having a recess 11 therein for receiving a reagent and the specimen. The glass plate 18 may be opaque or white glass and in this instance has a color card representative of known reduction characteristics painted directly upon the surface of the opaque plate as represented at l8, I9, 88, 8| and 82. Calibrations and symbols designating color and percentage of constituents are carried upon the opaque plate adjacent the characteristic color code thereon. In lieu of an opaque plate 18 a transparent slide may be provided and the color code carried by a card or scale over which the slide 18 is movable. The container for the set shown in Figs. 21 and 22 is indicated at 48 and is similar to the container for the sets shown in Figs. 12-14, and 15-20 in that-the container includes a compartment 48 for housing the drop-v transparent envelope 21 as heretofore described in connection with Figs. 1-5. A fabric or cloth member 28 is provided as part of the test set, all of the components of which are housed within container 83 closed by cover 83. The indicia carried by the calibrated chart or scale are similar to the indicia described in Figs. 1 and 4; and indicated in fragmentary form at -l9, 28 and 2|. In this arrangement the powdered reagent is placed in the crucible 88 when the carton 88 with cover 82 removed is removed from the container preparatory to a test. The specimen is added to the reagent and a reduction effected and then the calibratedchart moved over the top of the crucible 88 while viewing the residue in the crucible through the apertures 25, 28, etc. in the calibrated chart for matching the indicia with respect to the characteristics of the reduction and thus determining the percentage of constituents'in the specimen.

Throughout the several forms of my invention, calibrated charts are employed which show by color characteristic, percentage of constituents per vial 58 and the powdered reagent container 5| and also the fabric or cloth 68 all housed with the-plate 1 6, and in the instance where plate 18 is transparent with a calibrated scale or chart .convenlently disposed within container 88 and in for receiving respectively the container for the dry powdered reagent indicated at 86 and the dropper vial indicated at 81. I provide a special form of crucible indicated at 88 centrally supported in a relatively flat removable carton 89. The flat carton 88 contains a horizontally extending centering member 88 spaced from the bottom of the carton 88 and centrally apertured at 8| to receive the crucible 88. A cover member 82 normally covers the carton 88 with the crucible 88 closed therein as shown in Fig. 24. In the test set of Figs. 23 and 24, I employ a scale or chart similar to chart l8 of Fig. 4. The scale or chart I8 is completely covered by a and scale readings the known reactions between a specimen and the reagent employed. By way of example, I am listing the scale reading, color characteristic and percentage of constituents as follows:

Comparative chart for determination of sugar 8 The powdered reagent may be represented as follows:

One-tenth part 1 m 2 parts ypartc etals+ art ulverized momma. w H.032). p NaOH It is realized that variations may be made in the foregoing calibrations and the readings given will serve merely to illustrate the principles involved in the method and apparatus of my invention. I

The flat container shown at 8 in Figs. 1-3 and 8, and at 88 in Figs. 23 and 24 is utilized for eifecting the reduction. It is important that this container be maintained in a horizontal position and tipping prevented. For this reason the annular rim 1, or the horizontally extending centering member 88 is so designed that the container may be maintained in a horizontal position. In the form illustrated in Fig. 8 the rim I is elastic 'or resilient and snugly fits about the vertically extending wall of the container 8. The rim 1 thus serves a a practical means for preventing tipping. In the form illustrated in Figs. 23 and 24, the transversely extending member 88 insures the stabilized arrangement of the crucible 88 within the carton 88 and prevents specimen receiving plate. For example, in Figs.

14 and 19 the foldable portions. of cards 54 and 15 may carry printed explanatory directions for use of the test set. In the form of the chart illustrated in Fig. 14, both portions of the chart embrace the specimen receiving plate, but only one portion carries indicia. The other portion may carry printed directions and explanatory notes setting forth the manner in which the test apparatus is to be employed.

I have successfully utilized my invention in its several forms but I realize that modifications may be made in the arrangement and method employed and I desirethat it be understood that no limitations upon my invention are intended other than may be imposed by the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. Apparatus for chemical analysis comprising in combination with a flat plate having a recess centrally positioned thereon for receiving a chemical reagent and a specimen, a chart substantially conforming with the shape and size of the flat plate for super-position over said plate, said chart having a solid central portion in a, position adapted to be aligned with the position of the central recess in said flat plate when said chart is in super-posed co-extensive position on the plate and being apertured in a plurality of other positions along the length thereof, colored areas representing different degrees of reduction contiguous with each of the apertured portions of said chart, said colored are'as setting forth characteristics of known reductions, and the apertures in said chart being adapted to be selectively aligned with the recess in said plate for compar ing the characteristics of the reduction effected in the recess on said plate with the colored areas on said chart.

2. Chemical analysis apparatus comprising in combination a flat plate for receiving a powdered reagent and a specimen to be acted upon thereby, a foldable chart of protective material adapted to embrace said plate in folded position and to be superimposed thereover in testing position, the said fold of said chart carrying a multiplicity of colored areas representing different degrees of reductions, said colored areas each being apertured for optically observing and comparing the reduction between the reagent and specimen on said plate with the color areas on said chart, and the other portion of said foldable chart carrying directions for the use thereof.

3. Testing apparatus comprising a test conducting receptacle constituted as a transparent flat plate member having a recess therein for conducting drop reaction tests, and a foldable card having a pair of co-extensive portions each conforming with the size 01' said plate member and operative to embrace said plate member or to be unfolded and one portion viewed through said plate member, said one of the said coextensive portions having a substantially white central background for use as a test comparison area and indicia distributed along the said portion having color characteristics of known reactions of the reagent powder with solutions of known sugar content, said indicia being arranged for successive direct comparison with the drop reaction test performed in the recess in said fiat plate member upon relative shifting of the plate and card.

4. Testing apparatus comprising a test conducting receptacle constituted. by a transparent flat plate member having a recess therein for conducting drop reaction tests, and a foldable card having a pair of side portions each corresponding in size with the size of said transparent plate member, hinge members interconnecting the side portions of said card along one edge thereof whereby the side portions of said card are operative to embrace opposite sides of said plate member in folded position or whereby one portion may be viewed through said plate member when in unfolded position, said one of said side portions having a substantially white central background operating as a test comparison area and indicia distributed along said portion having color characteristics of known reactions of the reagent powder with solutions of known sugar content, said indicia being arranged for successive direct comparison with the drop reaction test performed in the recess in said flat plate member upon relative shifting of the plate and card.

5. Testing apparatus comprising a test conducting receptacle constituted by a flat plate member having a recess therein for conducting drop reaction tests and a foldable card havin a pair of co-extensive portions conforming with the size and shape of said plate member and opera tive to embrace said plate member when in folded position and whereby one of the co-extensive portions is superimposed on said plate member when in unfolded position, the last mentioned portion of said card carrying a multiplicity of differently colored areas representing different degrees of chemical reductions symmetrically arranged therealong, said differently colored areas each being apertured for permitting optical observation and comparison of the reduction in the recess in said plate with respect to the colors surrounding the apertures in said last mentioned portion of said chart by longitudinal movement of said card with respect to said plate.

ANTHONY V. PALMA.

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