924 SEC. 18. BIOLOGY. 



3639. Warm Moist Chamber, for observing microscopical 

 objects at an elevated temperature during long periods of time. 

 (Exhibitor's construction.) 



Prof. Dr. Fcrd. Cokn, of the Institute of Vegetable Phy- 

 siology in the University of Breslau. 



The apparatus in question combines the advantages of the moist chamber 

 and the warm stage of the microscope. The object is laid in a drop of water 

 on the underside of the glass plate in the centre of the cover, which has 

 been previously removed ; the cover is then firmly fixed, aiid the whole 

 apparatus placed on the stage of the microscope. 



It is warmed to the desired temperature, which is indicated by a thermo- 

 meter, by means of a small gas flame placed underneath the descending 

 heating tube. The object is observed through the glass plate in the cover, 

 which takes the place of a cover glass. By regulating the flame, the tem- 

 perature in the chamber, which is kept moist by the drop of water which 

 cannot evaporate, can be maintained perfectly constant for a long time, and 

 the development of microscopical organisms at a high temperature can be 

 observed. 



3640. Two Cases of Microscopic Objects. 



Voigt $ Ilochgesang, Gottitigcd. 



3640a. Cases of Microscopic Preparations. F. Enoch. 



3641. Microtome with Preparations, made by W. Apel, 

 mechanician to the University of Gottingen. 



Prof. W. Krquse, Gottingen. 



This microtome is accurately described by Prof. Krause in Waldeyer's and 

 De laValette's Archiv fur microscopische Anatomic (earlier in Max. Schultze's 

 Archiv), 1875, vol. XI., p. 216, plate XIII. It cuts in a purely mechanical 

 manner, more by drawing than by pressing the knife, whilst any shifting either 

 of the preparation or of the cutter by the hand is excluded by the principle 

 of the construction of the microtome. The tliickuess of the section to be 

 made can be read off on a circular disc divided into degrees, which can easily 

 be applied to the instrument. Any other (much longer) knife can be substi- 

 tuted for the one in the instrument ; the box in which the preparation is fixed 

 can also be changed. The knife can be moistened by means of an " irrigator " 

 with either alcohol or water, and the apparatus can be fastened to a Avail so 

 that the blade of the knife is horizontal. A microscopical preparation con- 

 taining two sections of different thicknesses made with the above apparatus is 

 enclosed for exhibition. 



3642. Holle's Drawing Apparatus for the Slicroscope. 



Cuno Rumann, Gottingen. 



The construction of the apparatus has just been completed, and only one 

 specimen has been made. 



An account of its leading peculiarities will be found in the paper enclosed. 



3643. Photograph of the Drawing Apparatus. 



Cuno Rumann, Gottingen. 



3644. Sectional View of Drawing Apparatus. 



Cuno Rumann, Gottingen. 



