ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 465 



capsules may be shown. Buerger's method properly applied is free from 

 these objections. Just before the smear dries the fixing fluid (Zenker's 

 fluid minus acetic acid) is added and heat is applied. It is then washed, 

 treated with alcohol, iodin is applied, and after further treatment with 

 alcohol the film is allowed to dry. It is then treated with anilin-gentian- 

 violet, washed with 2 p.c. salt solution, and mounted in salt solution. 

 Buerger describes a pneumococcus type, a streptococcus type, and a 

 mucoid type of capsule, and the present authors attribute to these a high 

 diagnostic value. 



Staining Embryonic Skeletal Structures.* --H. Lundvall describes 

 the following methods. For staining cartilage the material is placed in 

 0'25 p.c. solution of toluidin-blue in 1 p.c. hydrochloric-acid-alcohol 

 for several days at 40° C. and then decolorized in acid-alcohol. Alter- 

 natively, a rapid method with methylen-green and glacial acetic acid 

 may be used. For contrast-staining of bony and cartilaginous structures 

 the material is treated with alcoholic solution of alizarin and decolorized 

 in 95 p.c. alcohol. It is then counterstained with alcoholic methylen- 

 green to which is added a small quantity of glacial acetic acid, and washed 

 in 70 p.c. and 95 p.c. alcohol alternately. After this decolorization is 

 completed the bony structures appear red, the cartilage greenish-blue. 

 For dehydrating and clearing the tissue is then treated successively with 

 absolute alcohol, absolute alcohol and benzol two parts to one, absolute 

 alcohol and l»enzol one part to two, benzol, and finally with the clearing 

 fluid, which contains four parts of benzol saturated with peppermint-oil 

 and one part of carbon disulphide. 



Colloid Metal as Substitute for Indian Ink in Burri's Method.f 

 P. Xitsche states that " Collargol," a silver preparation, may ))e usefully 

 substituted for Indian ink in Burri's method.^ A smear of the material 

 to be examined is made on a slide ; the material may be diluted with 

 water. When the smear is dry the silver solution is spread over it, 

 and this also allowed to dry. The pictures of bacteria and spirochetes are 

 extremely sharp and larger than by Burri's method. If free acid should 

 be present in the material — e.g. coagulated milk— this should be mixed 

 with a few loopfuls of aqueous ammonia before allowing the smear to dry. 



New Method of Spore-staining.§ — Jun Hanzawa describes a pro- 

 cedure for staining spores, the novelty being a preliminary treatment 

 with iodo-potassic iodide solution. The spore-bearing organism is fixed 

 on a cover-glass, and then treated for from 1 to iJ minutes with Gram's 

 iodin solution. It is then washed successively in alcohol and in water. 

 It is next stained with methylen-blue (30 seconds), or with carbol- 

 fuchsin (1 minute), or with anilin-water-fucbsin (2 minutes), or with 

 anilin-water-gentian-violet (o minutes). Slight heat is used for promoting 

 the staining. If double staining be desired, this may be done by treating 

 the preparations which have been stained with fuchsin, with methylen- 

 l)lue (10 seconds, cold) ; while gentian-violet stained preparations are 

 contrasted with Bismarck-brown (i minute). After this the films are 

 washed in water and mounted in the usual way. 



* Anat. Anzeig., xl. (1912) pp. 639-46. 

 t Centralbl. Bakt., Ite Abt. Orig., Ixiii. (1912) pp. 575-6. 

 ■ J See this Journal, l9lO, p. 118. 

 § Centralbl. Bakt., 2te Abt. Orig., xxxiv. (1912) pp. 172-6 (1 pi.). 



