ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 259 



Studying Spermatogenesis in Acrididse and Locustidse.* — H. S. 

 Davis dissected out the testes in • G p.c. salt solution, and placed them 

 at once in the fixative. Many fixatives were tried, but only one, viz. 

 Hermann's platino-aceto-osmic was much used, though in a few cases 

 Flemming's fluid was adopted. After immersion in the fixative for 

 from 1 to 2 hours, the testes were passed through alcohol and imbedded 

 in paraffin. The best staining results were obtained from iron-hasmato- 

 xylin, preceded by Bordeaux R. The sections were immersed in 1 p.c. 

 Bordeaux R for 24 hours, then in the iron-alum for 1 or 2 hours, then 

 in the hsernatoxylin for from 4 to 6 hours. It was necessary to de- 

 hydrate very rapidly, as Bordeaux R is very solvent in alcohol. 



Studying Fat-absorption in the Intestine.! — G-. E. Wilson fed 

 guinea-pigs on egg-yolk diluted with tap water, or with olive oil. At 

 suitable intervals the animals were killed, and pieces removed from the 

 duodenum. The pieces were placed in the following fluid: 0*1 p.c. 

 chromic acid 15 parts; 2 p.c. osmic acid 4 parts ; glacial acetic acid 

 1 part, for about 12 hours. On removal the pieces were washed in running 

 water for half an hour, and then in upgraded alcohols from 50 p.c. to 

 absolute, this hardening and dehydrating stage taking about 132 hours. 

 The pieces were imbedded in paraffin or in celloidin. The sections 

 were stained with iron-alum, hematoxylin, and eosin, or with scarlet 

 (scharlach R). The scarlet should be dissolved in 70-80 p.c. alcohol, 

 shaken up from time to time and filtered. It should then be tested on 

 a slide with olive oil, when, if good, a deep red reaction ensues in about 

 a minute. For this dye the intestine may be fixed in formalin, and 

 frozen sections used. The scarlet solution is allowed to act for about 

 45 seconds, and then, after a few seconds in tap water, the section is 

 mounted in glycerin. 



Studying the Chorda-cartilage of Urodela.J — F. Krauss fixed the 

 material in picro-sublimate-acetic-acid and in Carnoy's fluid, and stained 

 the paraffin sections with kresyl-violet RR. This dye, which is a meta- 

 chromatising pigment, stains cartilage and also mucin a rose colour, 

 while the nuclei are blue. It was found better, however, to stain the 

 nuclei with hremaluin. Care must be taken to dehydrate rapidly, as 

 alcohol extracts the kresyl-violet rapidly. Methylen-blue and Bismarck- 

 brown were also used. To the methylen-blue a little hydrochloric acid 

 was added, and the stain fixed with molybdanate of ammonia. A triple 

 combination of borax-carrnin, Bismarck-brown, and light-green, gave 

 effective pictures. 



Demonstrating Hepatic Glycogen. § — N. Fiessinger fixes pieces of 

 liver for 24 or 48 hours in 95 p.c. alcohol, and then immerses them in 

 10 p.c. tannin for half an hour to one hour, according to their thickness. 

 They are then removed to 2 p.c. bichromate of potash for about 10 

 minutes. The pieces may then be washed, imbedded, and sectioned 

 without risk of dissolving out the glycogen. The sections are stained 

 with anilin oil-saf ranin, differentiated in alcohol, and mounted in balsam. 



* Bull. Mus. Comp. Zool. Harvard, liii. (1908) pp. 59-158. 



t Trans. Canadian Inst., viii. (1906) pp. 241-58 (2 pis.). 



t Arch. Mikr. Anat. u. Entwickl., lxxiii. (1908) pp. 69-116 (3 pis.). 



§ C.R Soc. Biol. Paris, lxvi. (1909) pp. 182-4. 



