CULTIVATION OF THE SPIROCH^ETE PALLIDA 521 



spirochaetes are of comparatively common occurrence. There is 

 no doubt whatever that the great majority of these are readily 

 distinguishable by their appearance from the spirochaete pallida, 

 but others resemble it closely. Hoffmann, however, who has 

 seen many of these spirochaetes from other sources, considers 

 that even by their microscopic appearance they are capable of 

 being distinguished, though with .considerable difficulty. It 

 must, of course, be borne in mind that the finding of an 

 organism in non-syphilitic lesions with the same microscopical 

 characters does not show that it is the same organism as the 

 spirochaete pallida. 



Cultivation. Levaditi and Mclntosh inoculated with syphil- 

 itic material human serum contained in sacs of collodion, which 

 were then placed in the peritoneal cavity of a monkey (Macacus 

 cynomolgus). After an interval of about three weeks, they found 

 in the sacs an abundant growth of spirochaetes morphologically 

 identical with spirochaete pallida, along with various anaerobic 

 bacteria. Schereschewsky claimed to have obtained impure 

 cultures of the organism in test-tubes, using for this purpose 

 horse serum inspissated at 58 C., and then allowed to undergo 

 autolysis for three days at 37 C. Recently Miihlens and 

 Hoifmann have obtained pure cultures of an organism morpho- 

 logically identical with the spirochsete pallida. They at first failed 

 to obtain pathogenic effects on inoculation with the cultures, 

 but later Hoffmann succeeded in producing a syphilitic lesion 

 in the testicle of the rabbit. By this time, however, Noguchi 

 had succeeded both in obtaining pure cultures and in giving 

 rise to syphilitic lesions by means of them. We shall accordingly 

 state his results, which in certain respects differ from those of 

 the other two observers. In the first instance his cultures were 

 made from syphilitic lesions in the rabbit, but later directly from 

 the lesions of the human disease. As a culture medium he used 

 a mixture of two parts of 2 per cent, agar and one part of ascitic 

 or hydrocele fluid, to which a small portion of sterile rabbit's 

 kidney or other organ was added, the medium being placed in 

 deep tubes and covered with a thick layer of paraffin oil. The 

 medium was inoculated through the oil, the maintenance of strict 

 anaerobiosis being essential. When contaminating bacteria were 

 present these formed a thick growth along the line of inoculation, 

 whilst the spirochaetes grew as a diffuse haze into the surround- 

 ing medium. By making sub-cultures from parts apparently free 

 from bacterial growth he succeeded in obtaining the organism in 

 the pure condition. At first the organisms were small, but after 

 several days they had the usual length of the spirochaete pallida 



