776 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Examining- the Oocyte of the Fowl.* — Sonnenbrodt obtained 



material from birds found dead in the fowl trains which come from 

 Russia to Berlin. For the ovaries of young animals sublimate acetic 

 acid was found to be the best fixative, but for ovaries with large follicles 

 calcium bichromate 2 p.c., sublimate 2 p.c, and acetic acid (20 : 10 to 1) 

 was superior. After having been passed through upgraded alcohols the 

 pieces were immersed in water-free aceton (£ to 1 hour), then in xylol 

 or chloroform (10 minutes to | hour), followed by a mixture with 

 paraffin (^ hour), and finally pure paraffin twice changed (| to 3 hours). 

 The sections according to the size of the follicles were cut from 2-10 ^ 

 thick. For sticking the thicker sections to the slide Olt's phenol- 

 gelatin was used ; the superfluous adhesive was removed by means of 

 blotting paper, and then the slide placed on edge was allowed to dry at 

 room temperature. When quite dry the preparations were treated with 

 10 p.c. formalin. Several staining methods were tried, but Heidenhain's 

 iron-alum-hsematoxylin was the only really successful one. Contrast- 

 staining was effected with orcein, rubin, orange, picric acid, acid-f uchsin- 

 picric-acid. 



(4) Staining: and Injecting - . 



Differential Staining Method for Acid-fast Bacilli.f — L. v. Betegh 

 recommends the following method for staining acid-fast bacilli. Smears 

 are made and dried and fixed in the flame ; they are then treated with 

 2 to 3 drops of 15 p.c. nitric acid and heated over a flame until slight 

 steam arises, and then washed with water ; they are then treated with 

 2 to 3 drops of methylen-blue or methylen- violet and 2 to 3 drops of 

 carbol-f uchsin, and again heated over a flame until the steam arises, after 

 which they are thoroughly washed and decolorised with 60 p.c. alcohol, 

 washed with water, dried, and mounted in balsam. 



For tubercle bacilli, perlsucht bacilli, avian tubercle, and leprosy 

 bacilli in sputum, the author recommends treating the specimen (after 

 the last washing with water) with a thick layer of water into which a 

 drop of malachite green solution has been added, and this to be followed 

 again with a washing with water. 



The bacilli stain red, the spores blue ; the nuclei of the leucocytes 

 are blue-violet or green-blue according to the duration of the action of 

 the malachite-green ; the cell plasma and other adventitious bacteria 

 stain light green. 



Silver Method for Differentiating the Bacilli of Leprosy and 

 Tubercle.^ — J- Yamamoto recommends the following process. Cover- 

 slip preparations of leprosy bacilli are made from nodules, after incision 

 with a sharp knife, care being taken to disinfect the skin, and to avoid 

 as much as possible the admixture of blood by pressure. Cover-slips of 

 tubercle bacilli are prepared from sputum or from pure culture spread 

 in egg-albumen. The preparations are dried and fixed in the flame ; 

 heated for 10 minutes in 5 p.c. nitrate of silver solution at 55-60° C. 

 They are then placed for 5 minutes in the reducing solution, which is 



* Arch. Mikr. Anat. u. Entwickl., lxxii. (1908) pp. 415-80 (4 pis.). 

 t Centralbl. Bakt., Ite Abt. Orig., xlvii. (1908) p. 654. 

 \ Tom. cit., p. 570. 



