926 SEC. 18. BIOLOGY. 



work of preparing is automatic, so that when a clear section surface i< 

 obtained, the movable box, by means of the vernier attached, can be raised a 

 definite fraction in height, and the object in it; the knife screwed up on the 

 slide is guided by means of the horizontal slot, whereby the uppermost part is 

 taken off as a thin section. After drawing back the knife to the other end 

 of the slot (turned from the operator), and a fresh raising of the box, a second 

 section is obtained in a similar manner, and so on until the object is con- 

 verted into thin sections. With objects difficult to cut it is necessary to 

 moisten the blade during the cutting of the section with weak spirit contained 

 in a wash bottle-, one tube from which overhangs the blade, whilst the other 

 is kept in the mouth for blowing. If the objects resist very much, so that 

 the blade tends to give, then the safety of the section will be secured by 

 laying the curved piece of metal from the mahogany box under the larger 

 screw of the eccentric disc, and a corresponding tightening of the adjusting 

 screw placed over the free end of the knife. The movable box can (for the 

 purpose of keeping the left hand for guiding) be easily fixed by means of a 

 clamping screw through the slot. 



Some sample sections are contained in the mahogany box. 



3651a. Microscopic Section Cutting Machine. 



G. Moritz Leyser, Leipzig University. 



3652. Counting Micrometer, for enumerating microscopical 

 forms. To this is added a figure under glass, representing the 

 micrometer magnified eight times. 



Prof. H. Welcker, Halle an der Saale. 



3653. Sliding Tray, carrying microscope lamp and Hartnack 

 microscope, for demonstrating objects to a class. 



W. R. M'Nab, M.D. 



This tray runs on two rollers partly covered with india-rubber, thus 

 destroying vibration, and permitting the tray to be used on an ordinary 

 table. 



3654. Mica-plates for preserving botanical and anatomical 

 preparations. (See Mineralogy.) Max. Raphael, Breslau. 



Mica-plates are conveniently employed for preserving hygroscopic ana- 

 tomical preparations, such as of foliaceous mosses (" Laubmoosen "), &c., 

 For this purpose, the mica is split halfway through, and the preparation placed, 

 in a moist condition, between the plates, which close of their own account 

 owing to the elastic nature of the mica. 



Should the preparations be required for examination, the plates have only 

 to be dipped for a second or two into water ; they may thus serve for years 

 for repeated microscopic examination. It is obvious that covering plates of 

 mica may be used for all botanical microsopic purposes. 



3654a. Hew adjusting and self-centering Shadbolt's 

 Turn-table for making microscopic cells. 



Harvey, Reynolds, and Co. 



3655. Knife for cutting microscopic sections, by Dr. Gower, 

 with divided adjusting screw. T. Hawksley. 



3656. Knife, with three blades, for cutting microscopic sections 

 by Dr. Madox. T. Hawksley. 



