<PICT:0702994/IV(c)/1> <PICT:0702994/IV(c)/2> A machine for automatically subjecting matter (e.g. in the preparations of tissue for microscopic examination) successively to the action of different preparations for predetermined periods comprises a plurality of receptacles arranged in a circle or <PICT:0702994/IV(c)/3> part circle, a hinged arm carrying a basket or like for the matter to be treated, means for raising and lowering the arm about its hinge to remove the basket from or insert it in a receptacle, means for rotating the arm from one receptacle to the next and a time control mechanism controlling the said movements. As shown the machine comprises a frame 10 having a circular top 14 supporting a number of beakers 16 arranged in a circle and containing the treating fluids. Rotatably supported by the frame is a cover disc 18 to which is hinged one end of an arm 20 having at the other a hook or the like 21 to which is attached a basket 22 containing the tissue or specimen to be treated. The arm 20 is raised and lowered about the hinge to remove the basket from or insert it into a beaker by an arm 44 operated by a crank 43 driven by an electric motor 11 which also drives a shaft 17 which rotates the cover 18 to move the basket from one beaker to the next, the cover having an aperture 19 through which the basket passes, the latter having a cover 23 to close the aperture when the basket is in a beaker. The arm 20 contains an electric motor 39 fed through contacts 41, 42 to rotate the basket 22 through a belt drive 40. Energization of the motor 11 to move the arm 20 and rotate the plate 18 to effect a sequence of immersions of the basket is controlled by one of two electric timing devices 12, 13, Fig. 5 according to the period over which treatment is to extend, the particular device being selected by a switch 24. Each device 12, 13 drives a disc 25, Fig. 3, having peripheral notches 26 adapted to be engaged by a pivoted lever 27, the latter, on such engagement, operating a microswitch 28 the arm of which moves from contact 28a to 28b, Fig. 5, and energizes the motor 11. The latter drives two cams 45, 46 the former, immediately the motor moves, opens a switch 49 to stop the timing device so as to hold the disc 25 stationary. The cam 46, after the motor has removed the basket from one beaker and inserted it in the next moves the arm of a switch 50 from contact 50a to 50b thereby stopping the motor. Simultaneously the cam 45 closes the switch 49 to restart the timing device and as the arm 27 rides out of the notch 26 the arm of switch 28 returns to the contact 28a and the motor 11 makes a small movement to return the cams 45, 46 to the "start" position, the latter cam returning the arm of switch 50 to the contact 50a. The sequence is repeated when the following notch 26 reaches the lever 27. To start the sequence of operation at a time after the timing device has been set in motion, the lever 27 may be held out of engagement with the disc 25 by engagement of a pin 32 with a pivoted arm 31. An arm 29 is adjustably mounted on the disc 25 and at the desired time engages a pin 30 on the arm 31 moving the latter to release the lever 27 to allow it to engage the edge of the disc 25. A similar device may be provided on the other timing device to stop the operation at a predetermined time.ALSO:<PICT:0702994/III/1> <PICT:0702994/III/2> <PICT:0702994/III/3> A machine for automatically subjecting matter (e.g. in the preparations of tissue for microscopic examination) successively to the action of different preparations for predetermined periods comprises a plurality of receptacles arranged in a circle or part circle, a hinged arm carrying a basket or like for the matter to be treated, means for raising and lowering the arm about its hinge to remove the basket from or insert it in a receptacle, means for rotating the arm from one receptacle to the next and a time control mechanism controlling the said movements. As shown the machine comprises a frame 10 having a circular top 14 supporting a number of beakers 16 arranged in a circle and containing the treating fluids. Rotatably supported by the frame is a cover disc 18 to which is hinged one end of an arm 20 having at the other a hook or the like 21 to which is attached a basket 22 containing the tissue or specimen to be treated. The arm 20 is raised and lowered about the hinge to remove the basket from or insert it into a beaker by an arm 44 operated by a crank 43 driven by an electric motor 11 which also drives a shaft 17 which rotates the cover 18 to move the basket from one beaker to the next, the cover having an aperture 19 through which the basket passes, the latter having a cover 23 to close the aperture when the basket is in a beaker. The arm 20 contains an electric motor 39 fed through contacts 41, 42 to rotate the basket 22 through a belt drive 40. Energization of the motor 11 to move the arm 20 and rotate the plate 18 to effect a sequence of immersions of the basket is controlled by one of two electric timing devices 12, 13, Fig. 5, according to the period over which treatment is to extend, the particular device being selected by a switch 24. Each device, 12, 13 drives a disc 25, Fig. 3, having peripheral notches 26 adapted to be engaged by a pivoted lever 27, the latter, on such engagement, operating a microswitch 28 the arm of which moves from contact 28a to 28b, Fig. 5, and energizes the motor 11. The latter drives two cams 45, 46; the former, immediately the motor moves, opens a switch 49 to stop the timing device so as to hold the disc 25 stationary. The cam 46, after the motor has removed the basket from one beaker and inserted it in the next moves the arm of a switch 50 from contact 50a to 50b thereby stopping the motor. Simultaneously the cam 45 closes the switch 49 to restart the timing device and as the arm 27 rides out of the notch 26 the arm of switch 28 returns to the contact 28a and the motor 11 makes a small movement to return the cams 45, 46 to the "start" position, the latter cam returning the arm of switch 50 to the contact 50a. The sequence is repeated when the following notch 26 reaches the lever 27. To start the sequence of operation at a time after the timing device has been set in motion, the lever 27 may be held out of engagement with the disc 25 by engagement of a pin 32 with a pivoted arm 31. An arm 29 is adjustably mounted on the disc 25 and at the desired time engages a pin 30 on the arm 31 moving the latter to release the lever 27 to allow it to engage the edge of the disc 25. A similar device may be provided on the other timing device to stop the operation at a predetermined time.