372 SUMMARY OF CURRENT RESEARCHES RELATING TO 



other cement is applied to the edges. In many cases it is worth while 

 to preserve a dry wing between cover and slide, a simple ring of wax 

 being sufficient. Except with larger and more markedly chitinous 

 insects, such as beetles, heating of the caustic potash solution is not 

 advised. 



Demonstrating the Structure of Corpus luteum of Sheep.* — 

 F. H. A. Marshall placed freshly excised uterus and ovaries in 10 p.c. 

 formalin, and after six days at least pieces of the uterine wall were 

 excised. These were then washed in water for about twelve hours, and 

 afterwards passed through alcohols of increasing strength. Sections, 

 made by the paraffin method, were stained with hsematoxylin and iron- 

 alum, hematoxylin and eosin, anilin-blue and borax-carmin. The 

 ovaries were generally treated in the same way, but sometimes were 

 fixed with sublimate. 



Demonstrating Presence of Seed-Fungus in Darnel.f — E. M. 

 Freeman placed the grains in a germinating chamber, and dissected out 

 the embryos or seedlings at various stages. The fixatives used were 

 Flemming's fluid and chromic acid (1 p.c. and \ p.c). An ilin- water 

 safranin and Heidenhain's hematoxylin were found to be the most 

 effective stains. In some cases chloral hydrate, potassium hydrate, and 

 lactic acid were used. For demonstrating the starchy endosperm the 

 sections were made with an ether-freezing microtome. 



Fixation of Infusoria.:}: — P. de Beauchamp recommends the follow- 

 ing procedure for fixing in the extended condition contractile animal- 

 cules, especially Vorticellae. The principal feature of the method 

 consists in slowly anaesthetising the animals, placed between a slide and 

 cover-glass. The use of the cover-glass prevents a too hasty action of 

 the reagent and avoids diffusion currents. The preparation is supported 

 on a couple of wedges placed inside a glass vessel containing a little 

 alcohol. The duration of the anaesthesia varies from \ to J of an 

 hour, according to circumstances. The animals are then fixed by 

 running a drop of the fixative under the cover-glass. The author used 

 only saturated solution of sublimate for fixing, which requires copious 

 and prolonged washing in order to get rid of it, but suggests that osmic 

 acid would act equally well. The preparations may now be stained 

 say with picrocarmin, and afterwards mounted in glycerin. 



Demonstrating the Tubular Reticulum in the Cytoplasm of 

 nervous and epithelial Cells of the Earthworm. § — S. Ramon y Cajal, 

 after calling attention to the existence of a tnbuliform apparatus in the 

 cytoplasm of the nervous and epithelial cells of the earthworm, gives the 

 following method for demonstrating the reticulum. The pieces of earth- 

 worm, which should not exceed 3 to 4 mm. in thickness, are incubated 

 for two to five days at 35° to 40°C. in 1*5 p.c. solution of silver nitrate 

 in distilled water. In certain cases stronger or weaker solutions may 

 be used with advantage, but it is always advisable to employ a large 

 quantity. When removed from the silver solution, the pieces should 



* Phil. Trans., cxcvi. (1904) p. 55. t Tom. cit., pp. 3-4. 



% Bull. Soc. Zool. de France, xxix. (1904) pp. 26-7. 



§ Bol. Soc. Espaiiola Hist. Nat. iii. (1903) pp. 395-8 (2 figs.). 



