TEXT-BOOK OF BACTERIOLOGY. 245 



from objection, speaks in favor of any condition as absolutely nec- 

 essary for the success of infection. This whole question is, besides, 

 of secondary importance to us. Even the strictest adherent of the 

 doctrine of predisposition has to deal not only with the disposed' 

 individual, but also with the infectious matter, the bacillus whose 

 action is required; and it seems idle to lose many words concerning 

 the greater or less amount of susceptibility to be brought forward 

 as a cause to produce an effect. 



Let us pass to the second question. If tuberculosis is not con- 

 sidered as an acquired, but as an inherited disease (whether trans- 

 mission is presumed to occur during- fecundation or only later, 

 during intra-uterine life), all our discussions concerning the develop- 

 ment of infection from the inhalation of bacilli, successful preventive 

 measures, etc., must appear incorrect and fall to the ground. But 

 not a single indubitable case of congenital tuberculosis (established 

 before or during birth) has thus far been observed in man. Johne 

 and Malvoz have, it is true, found tubercle bacilli twice in cattle in 

 the organs of embryos. The hereditarians of the strictest order have 

 for years danced most enthusiastically around the calf described 

 by Johne. 



But we can surely object that these observations are decided 

 exceptions to the rule, and, moreover, that we should take care not 

 to transfer conditions found in cattle to man. We are far from 

 saying that such a thing cannot happen; but it has as yet not 

 been established, and all cases of tuberculosis occurring during the 

 first months of life thus far communicated have proved open to the 

 suspicion that they were the result, not of an inherited affection, 

 but of one acquired at a very early period i.e., a genuine infection. 



How can we reconcile this theory of inherited tuberculosis with 

 the fact (familiar to everybody) that the disease so frequently 

 afflicts men in middle life ? Baumgarten attempts to account for 

 this by tracing the late appearance of tuberculosis to a long- 

 continued latency of the tubercle bacilli in the body. Their germs 

 are said to be transmitted by way of inheritance and to remain 

 dormant for years before they break forth at a time when the power 

 of resistance of the living tissue has become less, and then com- 

 mence their destructive activity. Analogous conditions with tardy 

 hereditary syphilis are referred to as supporting this view. But 

 apart from the circumstance that in the latter disease most of the 

 cases are by no means of a uniform character, we must not draw 

 conclusions from one infectious disease to another as long as their 

 conformity or similarity has not been established beyond a doubt. 

 Clinical experience and, above all, direct experiments showing no 



