254 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and thus examined. Methylen-blue in \ p.c. solution effectively 

 stained the parasites. 



For examining the parasites in the fixed condition, osmic acid vapour 

 was found to give the best results. The wet film obtained from the 

 style was in the vapour of 2-4 p.c. osmic acid for 1-4 minutes. Dried 

 films, after fixed in ethyl or methyl-alcohol, also gave good results. 

 The most successful stains were gentian-violet (Ohlmacher's formula, 

 which contains formalin), hematoxylin (Delafield's, Ehrlich's, and 

 Heidenhain's formulas), Giemsa, Leishman, alcoholic safranin, and 

 Loeffler's methylen-blue. For revealing structural details in the mem- 

 brane, gentian-violet and iron-hsematoxylin were most useful. The 

 various modifications of Eomanowski were much less successful than the 

 hematoxylin stains. Sections were made of the style of Anodin which 

 had been fixed in Flemming's fluid : these were stained with hema- 

 toxylin solutions, Giemsa and methylen-blue. 



Demonstrating the Histogenesis of Nerve-fibrils. * — D. J. Pesker 

 opened the abdominal cavities of gravid white mice killed with chloro- 

 form, and removed the embryos separately or together with the 

 membranes and the uterus. 



The material was fixed in the following fluid : alcohol (96 p.c.) 

 96-97 c.cm. ; ammonia (10 p.c.) 4-3 c.cm. In this fluid, changed after 

 24 hours, the embryos were left for 2 days. The larger embryos were 

 cut in several pieces after 24 hours. On removal from the fixative, the 

 pieces were washed in water and then transferred to 1| p.c. silver- 

 nitrate and kept for 3 or 4 days at 37° C. When withdrawn from the 

 silver solution, the objects were mopped up with blotting-paper and 

 placed in the following solution for 24 hours in diffuse daylight : 

 pyrogallic acid, 2 ; formalin, 5 ; distilled water, 100. Paraffin sections 

 were then prepared in the usual way, and these were treated for 5 to 15 

 minutes with 1 p.c. gold-chloride solution, from which they were directly 

 transferred to 5 p.c. hyposulphite of sodium for 10 to 12 minutes. The 

 sections were then submitted to prolonged washing in water, and after- 

 wards mounted in the usual way. 



(3) Cutting-, including: Imbedding- and Microtomes. 



Demonstrating the Microscopic Structure of Fossil and Recent 

 Reptilian Bone.f — A. L. L. Seitz remarks that one of the greatest 

 difficulties in obtaining microscopical preparations of fossil bones is 

 their fragility, and tendency to crumble in manipulation. His method 

 was to surround the pieces with a mixture of resin and wax (9-1), and 

 then to remove slices with fine fret-saws, or with circular saws and emery. 

 The slices thus obtained were stuck on stout slides with a mixture of 

 resin, wax, and hard balsam (9-1-1), and then ground down with emery 

 on rough glass, and afterwards, if necessary, polished with smooth glass. 

 The flattened surface was then fixed with the resinous mixture to 

 another slide, and the first one removed by careful heating and manipu- 

 lation. The other surface of the slice is then ground down on an 

 emery wheel with water until it is about 1 mm. thick, when it is 



* Archiv Mikrosk. Anat. u. Entwickl., lxxi. (1908) pp. 333-49 (1 pi.). 

 t Nova Acta Leopold-Carol. Acad., lxxxvii. (1907) pp. 229-400 (14 pis.). 



