. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14. Botany; Botany. 110 PLANT PHYSIOLOGY the pistons is conveyed to a separate machine where three metal dia- phragms, similar to those of aneroid barometers, are forced out or drawn in, and thus control, by means of levers, the rod to which the microneedle or pipette is clamped. The manipulator operates with remarkable precision, being wholly free from lost motion. The independence of operating and receiving mechanisms eliminates vibration. The hand of the operator and the needle-poi
. Contributions from the Botanical Laboratory and the Morris Arboretum of the University of Pennsylvania, vol. 14. Botany; Botany. 110 PLANT PHYSIOLOGY the pistons is conveyed to a separate machine where three metal dia- phragms, similar to those of aneroid barometers, are forced out or drawn in, and thus control, by means of levers, the rod to which the microneedle or pipette is clamped. The manipulator operates with remarkable precision, being wholly free from lost motion. The independence of operating and receiving mechanisms eliminates vibration. The hand of the operator and the needle-point move in the same direction and the operator's hand need never leave the one lever with which all movements are performed, de Fon- BRUNE has also constructed an instrument for automatically drawing needles and pipettes under the microscope lens. In addition he has devised a simple method for protecting preparations of living material from dehydration without the use of a moist chamber. He simply places the material under an oil drop (nujol) either on the upper side of a slide or as a hanging drop. The oil is harmless, and lack of air has no ill effect for some time. Unfor- tunately the DE FoNBRUNE micromanipulator is not yet commercially obtainable. It is impossible to say which instrument is the best. The last mentioned gives promise of being so, but it has not yet been used by anyone except its inventor. Among the others, it is primarily a question of the instrument upon which one has learned. The Leitz-Chambers instrument is stable; the Zeiss-P^terfi has the greatest freedom of movement. Accessories to micromanipulators are many. The fewer bought the better (certain ones sold are worthless). Exceptions are the needle-holders of Zeiss and the micropipette equipment of Leitz. Needles are best made by the individual investigator, because the type of needle should fit the work to be done, and the various types can be made only by hand. However, automatic devices such as drawin
Size: 1023px × 2444px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookpublisherphiladelphiasn, booksubjectbotany
