82 THE AMERICAN MONTHLY [Mar 



first suggested the use of sudau iii in histological and 

 pathological work, recommends that Muller's fluid and 

 glycerin be used in hardening and fixing the tissues, and 

 that absolute alcohol should not be used as a dehydrating 

 agent, nor should the specimen be cleared in the essen- 

 tial oils or xylol nor mounted in Canada balsam. 



I. Staining of Tubercle Bacilli in Pure Cultures. — 

 Cover-glass preparations were made and fixed in the or- 

 dinary way and then immersed in a cold, saturated 

 eighty-per-cent alcoholic solution of sudan iii for five 

 minutes. The excess of stain was then removed by 

 washing in several changes of seventy-per-cent alcohol 

 for five minutes. The results obtained were very satis- 

 factory, and the characteristic appearance of the tuber- 

 cle bacilli could be very readily noted. The bacilli are 

 stained somewhat better if left in the sudan iii for ten 

 minutes and then washed in the seventy-per-cent alco- 

 hol. The germs are found stained a bright red and the 

 beaded appearance is very distinct. Cultures of the 

 bovine tubercle bacillus, and also of the tubercle bacillus 

 obtained from swine, .treated with this dye, were not ap- 

 parently as well stained as in the case of the bacillus of 

 human origin. The latter stained with sudan iii are not 

 decolorized by washing for two minutes with dilute one- 

 to-twenty-five sulphuric, hydrochloric, or nitric acid, or 

 ammonia. 



II. Staining of Preparations from a Gland of a Tu- 

 berculous Guinea-pig, and from Sputum, which had been 

 proved to Contairi Tubercle Bacilli. — The preparations 

 were fixed as usual and immersed for ten minutes in a 

 saturated eighty-per-cent alcoholic solution of sudan iii. 

 They were then washed from five to ten minutes in 

 seventy-per-cent alcohol. Upon examination the tuber- 

 cle bacilli were found to be stained a distinct red and 

 presented the characteristic appearance. No other bacilli 

 present in the sputum had been stained by the sudan iii, 



