240 SUMMARY OF CURRENT RESEARCHES RELATING TO 



over the surface of that side of the slide which has been exposed to the 

 vapour, aud a film made. The film side is theu at ouce exposed to the 

 vapour for ^h minute and then allowed to dry in the air. It can then 

 be examined iii water. If a permanent preparation be desired, the film 

 must be stained. The stains recommended are Ehrlich's tri-acid, and 

 Griemsa's solutions. 



Studying Ascomycetes.* — J. H. FauU, in his study of development 

 of ascus and spore formation in-Ascomycetes, used several fixatives, but 

 found that Flemming's weaker solution was the most satisfactory. As 

 stains, Flemminir's triple stain of safranin, gentian-violet and orange CI, 

 and Heidenhain's iron-hsematoxylin were superior to all others, but no 

 hard and fast rule can be laid down, as each species requires special 

 staining treatment. Paraffin (m.p. 57°) was used for imbedding, and 

 the sections were from :->-"> fx thick. 



In determining the origin of the ascus it was frequently of advantage 

 to crush slices of fresh or preserved material, preferably the latter, and 

 examine in water or potash. 



Studying the Anatomy of Boophilus Annulatus.f — S. R. Williams 

 killed the material (gravid females, immature females and males) in hot 

 water, Perenyi's corrosive-acetic, Carnoy's and Hermann's fluids. Poor 

 sections were obtained from fresh material owing to the thick chitinous 

 investment. But with museum specimens which had been kept in 

 spirit for ten years, sections serviceable for study of the general forni of 

 organs were obtained by dissecting off the cuticula. The cytological 

 condition was indifferent, but the series were perfect and easily obtained. 

 The suggestion is made that adult females should be fixed in warm 

 solutions and then left in strong alcohol for some days, so that, owing to 

 shrinkage, the chitin can be dissected off with fine needles under a 

 Microscope. 



Studying the Anatomy of Mosquito-t — M. T. Thompson cut off 

 the dorsum of the thorax while the insect was immersed in the fixa- 

 tive. The reagent used was Gilson's fluid, made as follows : 70 p.c, 

 alcohol, 10 parts ; distilled water, 86 parts ; corrosive sublimate, 2 parts ; 

 glacial acetic-acid, h part; nitric acid (80 p.c.) U part. Before 

 immersion in the warm Gilson's fluid, the insect was dipped in alcohol 

 to remove air from the scales. Serial sections were cut in the three 

 planes usually employed. Other sections, 30 /x, were made from material 

 fixed in Flemming's fluid, and were mounted without further staining 

 than that derived from the fixative. An excellent method of mounting 

 the whole head of the larva is to stain with picro-carmin and clear 

 with Weigert's fluid. 



The pupa stage was studied from serial sections of a series of 

 specimens of known age. Such a series was obtained by segregating 

 mature larvae in a dish, and each hour removing all pupae to separate 

 containers in which they could be reared for any desired number of 

 hours. 



* Proc. Boston Soc. Nat. Hist., xxxii. (1905) pp. 77-113 (5 pis.). 



t Tom. cit., pp. 313-34 (5 pis.). % Tom. cit., pp. 145-202 (6 pis.). 



