522 SYPHILIS 



and all its characteristics. An important point is that he found 

 clear evidence that the organism multiplies by longitudinal 

 division. On inoculating monkeys (macacus and cercopithecus) 

 by scarification, indurated syphilitic papules developed and the 

 blood of the animals gave a positive Wassermann reaction. The 

 etiological relation of the organism has thus been completely 

 established. 



Transmission of the Disease to Animals. Although various 

 experiments had previously been made from time to time by 

 different observers, in some cases with reported successful result, 

 it is to the papers of Metchnikoff and Roux (1903-5) that we 

 owe most of our knowledge. These observers have carried on a 

 large series of observations, and have shown that the disease can 

 be transmitted to various species of monkey. Of those the 

 anthropoid apes are most susceptible, the chimpanzee being the 

 most suitable for experimental purposes. Their results have 

 been confirmed by Lassar, Neisser, Kraus, and others. The 

 number of experiments on these animals is now very great, and 

 the general result is that the disease has been transmitted by 

 material from all the kinds of syphilitic lesions in which spiro- 

 chsetes have been demonstrated, including even the blood in 

 secondary syphilis and tertiary lesions. Inoculation is usually 

 made by scarification on the eyebrows or genitals ; the sub- 

 cutaneous and other methods of inoculation give negative 

 results. The primary lesion is in the form of an indurated 

 papule or of papules, in every respect resembling the human 

 lesion. Along with this there are marked enlargement and 

 induration of the corresponding lymphatic glands. The primary 

 lesion appears on an average about thirty days after inoculation, 

 and secondary symptoms develop in rather more than half of the 

 cases after a further period of rather longer duration. These 

 are of the nature of squamous papules on the skin, mucous 

 patches in the mouth, and sometimes palmar psoriasis. As a 

 rule, the secondary manifestations are of a somewhat mild 

 degree, and in no instance up to the present has any tertiary 

 lesion been observed. By re-inoculation from the lesions, the 

 disease may be transferred to other animals. The disease may 

 also be produced in baboons and macaques, but these animals 

 are less susceptible, and secondary manifestations do not appear. 

 The severity of the affection amongst apes would in fact appear 

 to be in proportion to the nearness of the relationship of the 

 animal to the human subject. The blood of the infected animals 

 comes to give a positive Wassermann reaction. 



As shown first by Hansell, and afterwards by Bertarelli, the 



