and Laboratory Methods. 1765 



solution 6 cm.-^ of 1 per cent, eosin are added and thoroughly mixed. This affords 

 sufficient stain for use in a flat porcelain staining dish, in which the slide is 

 placed preparation side down. The metallic film on the stain should be removed 

 with filter paper before the slide is taken from the dish. It is then rinsed in 

 water and placed in the differentiating fluid (120 cm.-^ 95 per cent, alcohol, to 

 which 4 to 5 drops of glacial acetic acid and 2 cm.^ of 1 per cent, aqueous solu- 

 tion of eosin have been added). The slide is moved to and fro with forceps 

 and the superfluous stain comes off in blue clouds, the preparation changing from a 

 violet to an eosin-red. Before this last trace of violet is washed out, the slide should 

 be removed to water and thoroughly washed till no more color comes off. It is 

 then dried between filters and mounted in balsam, c. a. k. 



Christophers, S. R The Anatomy and Hist- ^he examination of fresh tissues reveals 

 ology of the Adult Female Mosquito. Re- 

 ports to the Malaria Committee, Royal Soc. Structures not readily discerned in 



London, Fourth Series, pp. 1-20, 6 pis., fixed preparations. Dissections should 

 1901. '■ ^ 



be made in saline solutions of 0.3 or 



0.4 per cent., as insect fluids have a lower isotonic point than those of mammals. 



Smear preparation of the salivary glands and mid-gut may be made from these 



organs after dissection. They should be spread by means of the edge of a slide 



or cover-glass, dried rapidly, fixed, and stained in haematein. Sporocysts and 



sporozoites, as well as other parasites in mid-gut and hind-gut, are well 



demonstrated by this method. Aqueous solutions should be avoided as fixing 



agents for whole mosquitoes on account of their failure to penetrate the 



exoskeleton. Absolute alcohol gave best results. As soon as the insects are 



partially hardened the thorax and abdomen should be opened by minute incisions 



to insure complete fixation of the tissues. Isolated organs are finely fixed by 



corrosive sublimate or picric acid. Culex and Atiopheles, especially the latter 



cut readily in either celloidin or paraffin. Stellate cells of tracheal endings are 



shown by gold chloride. Haematein gives the best stain for the malarial parasite, 



and Heidenhain's haematoxylin is recommended for salivary glands and muscle 



fibres. c. a. k. 



Stevens, N. M. Studies on Ciliate Infusoria. Two ciliates parasitic in the respiratory 

 Proc. Cal. Acad. Sci. Third Series ; Zool- tree of Holothiiria californica were 

 gy. • 4-. P • . 9 • secured in large numbers, usually to- 



gether in the same host. The respiratory tree was removed from the living host, 

 plunged into the fixing fluid, washed, hardened in alcohol, embedded and cut in 

 sections 5 to 7 A' in thickness. For iri toto preparations portions of the tree were 

 stained and afterwards teased out in glycerine or clove oil. A very large num- 

 ber of fixing agents were tried. Hermann's fluid gave best results, though sub- 

 limate-acetic, absolute acetic, Boveri's picro-acetic, Flemming's, and Von Rath's 

 solutions proved quite satisfactory, and osmic vapor was especially valuable for 

 temporary in toto preparations for the study of division stages. Two per cent, 

 potassium bichromate was most effective as a macerating agent, revealing inter- 

 nal fibre structures satisfactorily. For fresh material picro carmine and alum 

 carmine were the best stains; for in toto, borax carmine, paracarmine, light 

 green and safranin ; while for sections no other stain was comparable with 



