ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 353 



one of the principal advantages of celloidin, while the colour from 

 picro-nigrosin completely disappears under the action of the alcohol 

 and formic acid. 



Staining Mucous Glands and Goblet-cells.* — Dr. E. Paulsen has 

 succeeded in staining deeply the network of mucous glands (lingual 

 and siibmaxillary of calf) with Delafield's hsematoxylin after fixing in 

 1 per cent, osmic acid or in Flemming's osmium mixture and harden- 

 ing afterwards in alcohol for some days. Alcohol preparations were 

 treated after Heidenhain's method. The osmic acid mixture is pre- 

 ferable to the osmium mixture. Good stainings were obtained in a 

 dilute solution after immersion for twelve to fifteen hours ; in the 

 undilute solution the same effect was attained in about half an hour. 

 By this the reticulum of the epithelium of mucous gland was sharply 

 stained, while the intervening substance remained clear and un- 

 coloured. The receptivity for colour is unequal, some cells staining 

 more than others, while some are altogether unaffected by the stain. 



The author has also with 1 per cent, osmic acid and haematoxylin 

 staining after Heidenhain's method, been able to show in Bowman's 

 glands of many mammals that the epithelium uuites in itself the 

 characteristic properties of both kinds of lingual glands, both kinds, 

 and even a third with a central mucous zone, occurring within the 

 gland-sheath. 



Goblet-cells, which appear in large numbers in nasal mucous 

 membrane, are by the same treatment stained blue or blue-violet. 



Staining Capsule Micrococci.f — Dr. C. Friedliinder recommends 

 the following for cover-glass preparations : — Pass thrice through the 

 flame ; immerse in a 1 per cent, solution of acetic acid for one or two 

 minutes ; then blow oft' the acetic acid with a pipette, and dry in the 

 air. Stain for some seconds in the solution of anilin-water and 

 gentian-violet. Wash again, and examine. The ground-substance 

 is colourless, hence the stained parts, e, g. the capsules, stand out very 

 distinctly. 



For demonstrating capsule cocci in sections Friedliinder gives the 

 following method : — Stain for twenty-four hours in acid solution of 

 gentian-violet (concentrated solution of gentian-violet in alcohol 50 ; 

 aq. destil. 100 ; acid acetic 10). Then decolorize in 1 per cent, 

 acetic acid for 1-2 minutes, dehydrate in alcohol, and clear up in oil 

 of cloves. Some practice is required to hit off the requisite degree of 

 decolorization. 



Staining Spirilla in Blood-preparations.J — Dr. C. Giinther re- 

 commends that the cover-glass preparations of blood containing 

 spirilla, made in the usual manner and fixed over a flame (or better • 

 by five minutes in a thermostat at 75° C), should be washed for ten 

 seconds in a 5 per cent, solution of acetic acid before being stained. 

 This diives out the haemoglobin from the blood-discs, which are no 

 longer coloured by the stains, so that when the staining of the 

 preparations is completed the most highly coloured spirilla no longer 



* Zeitsch. f. Wi33. Mikr., ii. (1885) pp. 520-1. 

 t Fortschr. d. Med., iii. (1885) p. 757. J Ibid., p. 755. 



Set 2.— Vol. VI. 2 A 



