122 Society for Experimental Biology and Medicine. 



lepra nodule. I thus sought a leper who would, for a small 

 inducement, place himself under treatment and succeeded in gain- 

 ing a beggar for what thus became in truth an experimentum in 

 corpore vili, for he is an advanced and wretched case of the tuber- 

 cular form of the disease. I excised a nodule from his arm ; found 

 it very rich in bacilli ; ground it with sand and salt solution ; cen- 

 trifugalized ; heated to 65-70 0 C. for fifteen minutes, and added 

 enough 5 per cent, carbolic acid to make a suspension containing 

 0.5 per cent, of the acid. This suspension is rich in bacilli ; of it 

 I make at intervals subcutaneous inoculations of 0.0 1 ccm., the 

 intervals depending on the general condition of the patient. Ex- 

 perience with the more exact methods possible with the analogous 

 disease, tuberculosis, indicates that minimal inoculations of the 

 dead bacilli must be continued over a long period before a genuine 

 arrest is attained ; even, therefore, with the most favorable outcome, 

 I cannot expect to record the results of this treatment for months 

 to come ; on the other hand, the case was already so advanced 

 when inoculation was begun that I am not sanguine of any pro- 

 nounced favorable results. I would only repeat that the method 

 appears to deserve publication, that others with fuller opportunities 

 may test and, it may well be, improve upon it. 



86 (229) 



Direct silver staining of spirochetes and flagellated bacteria. 

 By SIMON FLEXNER. 



\From the Rockefeller Institute for Medical Research^ 



The discussion of the nature of the structure now called spi- 

 rochete (Treponema) pallida — whether a microorganism or some 

 histological elements — led me to try to effect the silver staining 

 directly upon smear preparations prepared from serum exudates 

 obtained from syphilitic lesions. While engaged unsuccessfully 

 in this endeavor, Stern 1 of Prag published a simple method for 

 staining the spirochetes directly with silver nitrate. When the 

 deposit of silver presents a metallic sheen, the impregnation is re- 

 garded as sufficient. I have found the method very simple and 

 sufficient ; but I have obtained better results from long (3-4 days) 



I Stern I Berl. klin. Woch. y 1 907, xliv, 400. 



