2«56 SUMMARY OF CURRENT RESEARCHES RELATING TO 



C3) Cutting:, including: Embedding- and Microtomes. 



Collar Cavities of Larval Amphioxus.*— K. M. Smith and H. G. 

 Newth examined four larval stages. Larvae which had been fixed in 

 Hermann's fluid were obtained from the Naples Zoological station. 

 They were cut into series of transverse sections by the method of double 

 embedding in celloidin and wax, and the sections 4 /x or 5 /x thick 

 were stained variously with Delafield's hsematoxyhn, thionin, alcohohc 

 ha3matein, or with an aqueous solution of picro-nigrosin for the special 

 purpose of making plain the relations of the myosepta. 



(4) Staining: and Injecting:. 



Staining of Spirochseta Ictero - hsemorrhagica.f — L. Martin, 

 A. Petit and A. Vandremer have adopted the following technique for 

 the preparation and staining of Spirochseta Idero-hsemorrhagka : — 1. A 

 part of the liver of an infected guinea-pig, autopsied six hours after 

 death, is roughly ground and mixed with 10 c.cm. salt solution. 2. It 

 is then filtered, the filtrate showing with the ultra-microscope the 

 presence of numerous active spirochetes. 3. The filtrate is centrifuged 

 for ten minutes, a precipitate divided into two portions being obtained, 

 a deep red layer and a superficial white layer. The supernatant fluid is 

 yellowish and cloudy. 4. The supernant fluid is pipetted off and replaced 

 with salt solution, the processes being repeated until the overlying fluid 

 is clear and colourless. A small portion of the superficial layer of the 

 precipitate (in which the spirochastes are collected) is then taken up with 

 a pipette. Thin slide preparations are prepared, dried and stained by 

 Lee filer or van Ermengen method. 



A. Lceffler's method : — Fix with alcohol and ether, cover with 

 fuchsin solution and warm gently, wash with distilled water, rinse 

 three times with absolute alcohol, cover with alkaline gentian-violet and 

 warm gently. Wash with distilled water and dry. 



B. van Ermengen's method : — Follow the classical method of 

 staining for flagella, but instead of employing carbol-fuchsin, use 

 diluted alkaline gentian- violet. 



»"■ 



Demonstrating Nuclei of Nerve-fibres.J — H. E. Reburn recommends 

 the following method for general routine work when a rapid result is 

 wanted. The fresh nerve is teased on a slide in the usual way, the 

 preparation being kept moist with the breath. A drop of absolute 

 alcohol is added, and then a drop of Ehrlich's hsematoxylin, followed by 

 a drop of methylen-blue. Either dye may be used alone, but the 

 nuclei are most deeply stained when both are employed. An alcoholic 

 solution of eosin may be substituted for the absolute alcohol ; the 



* Quart. Journ. Micr. Sci., Ixii. (1917) pp. 243-51 (1 pi.). 

 + C.R. Sec. Biol. Paris, Ixxix. (1916) pp. 1053-5. 

 X Quart. Journ. Micr. Sci., Ixii. (1917) pp. 217-9. 



