﻿TREPONEMA PEUTENTJIS CASTELLANI OF YAWS. 457 



noticed. However, the limit of error in this respect is small and of no 

 practical importance. The approximate period of incubation in our five 

 successful inoculations was as follows : 



Days. 



Monkey No. 1 (3070) 10 



Monkey No. 2 (3071) 20 



Monkey No. 3 (3072) 20 



Monkey No. 4 (3073) T 20 



Monkey No. 5 (A) 35 to 45 



In the ease of monkey No. 5 (A), the yaws lesion, when first noticed, 

 was- about the size of a small pea and had obviously been present for a 

 number of days. 



Comparing our results with these of Neisser, Baermann and Hal- 

 berstadter(28), it is noticeable that in our monkeys the period of incuba- 

 tion was much shorter, as a rule, although the same low type of animal 

 was iised. Indeed, the incubation period of yaws in Cynomolgus phil- 

 ippinensis Geoff., approaches more nearly that in Gibbons, as is shown 

 by the investigators mentioned. Thus, in the lower types of monkeys used 

 by them, the incubation period in five animals was found to be twenty-two, 

 thirty-one, sixty-five, ninety-one and ninety-six days respectively, while 

 in only one of our five animals did it probably exceed twenty days. If we 

 add to this result the probability that the lesions in all of our cases may 

 have existed for a day or two before they were noticed, thus shortening 

 the period- of incubation still further, the difference in our results and 

 those in the German commission becomes more noticeable. The regula- 

 rity of the period in our animals is also worthy of notice, four of them 

 developing the disease between the fifteenth and twentieth day after 

 inoculation. 



Duration of the disease. — In the five monkeys in which we produced 

 frambcesia by inoculation the duration of the lesion was as follows : 



Monkey No. 1 (3070), eighty-four days; No. 2 (3071), fifty-seven days; No. 3 

 (3072), ten days (this animal was chloroformed while the lesions were still 

 active) ; No. 4 (3073), thirty-nine days; No. 5 (A), fourteen to twenty-one days. 



It was invariably our experience that in the more severe cases the 

 primary lesion tended to spread into the surrounding skin, and the more 

 marked this tendency was, the longer the disease lasted. We failed to 

 observe any general glandular enlargement or any symptoms pointing to 

 a general infection. 



The lesions of frambcesia as observed in monkeys. — The lesions pro- 

 duced by the experimental inoculation or frambcesia in monkeys do not 

 differ essentially, in their morphology, from those occuring in the disease 

 in man, but we have never observed the secondary or generalized erup- 

 tion, which, according to most authors, follows the primary lesion in 

 the human subject. Neisser, Baermann and Halberstadter regard as 

 secondary eruptions the extension of the infection from the site of the 



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