432 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



the chamber is being filled. The labour of pumping may be reduced 

 by placing the ball-pump between two pieces of wood hinged like 

 lemon-squeezers. Material has been frozen in a room at 96 F. using 

 ether of • 730 sp. gr. 



Swift and Son's Improved Microtome. — In the microtome just 

 described the sections are cut and their thickness regulated by the 

 gradual descent of the knife towards the tissue to be operated upon. 

 In order to reverse this process and provide a machine in wliich the 

 tissue shall ascend towards the knife — as is the case in the ordinary 

 form of section-cutters — Messrs. Swift and Son have brought out 

 their new microtome, a drawing of which is given in Fig. 84, and which 



is described as follows by Dr. S. Marsh in the new edition of his 

 useful little work on section-cutting. 



" The instrument consists of a massive iron upright, terminating 

 at its lower extremity in a clamping arrangement, by which it may be 

 securely fastened to the table. From the top of the upright two highly 

 polished iron bars, lying parallel to each other, run horizontally for- 



