10G SUMMARY OF CURRENT RESEARCHES RELATING TO 



(2) Preparing Objects. 



Researches on the Leucocytes and Lymphoid Tissue of Inverte- 

 brates.* — M. Kollinann fixed the material with Zenker's fluid (with and 

 without acetic acid), Lindsay's fluid, and in certain cases with Dekhuysen's 

 mixture (potassium bichromate 6 • 25 grm., filtered sea-water 250 c.cm., 

 2 p.c. osmic acid 54 c.cm.). The last fluid is isotonic with sea-water, 

 and gives excellent results for very delicate elements. In some cases, 

 ■Gastropods, Lamellibranchs, and Echinoderms, the plasma being de- 

 ficient in albumen coagulates in flakes, and does not stick to the slide. 

 Various devices to meet this emergency must be resorted to, the only 

 one mentioned being that of Regaud, which consists in collodionising 

 the slides. For staining the films the following were used : hsematoxylin- 

 eosin-orange, toluidin-blue-eosin-orange, saf ran in-light-green, magenta- 

 Benda. For the granules, the triacid, the C mixture of Ehrlich and 

 Giemsa, were used. For the lymphogenic organs, the same fixative 

 which succeeded best with the blood was used, while for demonstrating 

 the stroma, 2 per thousand potassium bichromate, or Merkel's fluid, was 

 substituted Sections were made by the gum method, but if the 

 presence of a network can be detected by the naked eye, the paraffin 

 method may be adopted. 



The author then describes his method of making a differential count 

 of the corpuscles. A drop of blood is obtained by means of a pipette ; 

 this is spread on a slide fixed with osmic acid vapour, dried and stained 

 with triacid. All the corpuscles in the whole of the film are then 

 counted and classified. It is advisable to count several thousand. 



(4) Staining- and Injecting:. 



Bacillus of Anthrax and Silver Impregnation. — J. Yamamoto 

 finds that young vegetative forms of Bacillus anthracis are silver-nega- 

 tive, only the contour staining as a sharp black line ; in older forms, 

 when spore-formation is commencing, the entire bacillary body is dif- 

 fusely stained, more especially at the centre, but also at other points 

 black flecks are found which later become larger and circumscribed, and 

 appear as spores. In older cultures they stain less well. These ob- 

 servations applied to cultures on all the media investigated. 



The bacilli in smears from heart-blood or in organs from an anthrax- 

 infected mouse, are not so constantly silver-negative, many organisms 

 showing a black stain ; the capsule remains unstained, as is the case 

 with other encapsuled bacteria. 



Staining of Fat with Basic Anilin Dyes.f — J. Lorraiu Smith says 

 that if a section of fat-containing tissue be stained with an aqueous 

 solution of a basic anilin dye, and then exposed to the air in a thin layer 

 of Farrant's solution for 2 or 3 days, the fat will attract the dye from 



* Ann. Sci. Nat. Zool., viii. (1908) 210 pp. (2 pis.). 

 + Centralbl. Bakt., lieAbt. Orig., xlviii. (1908) p. 253. 

 X Journ. Pathol, and Bact., xii. (1907) pp. 415-20. 



