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bacillus the object whose presence is followed by tuber- 

 culosis, we may not forget that the appearance of the 

 disease implies not only the presence of this organism, 

 but also the existence of animal tissues which permit 

 the bacillus to exercise its vital functions. Many ani- 

 mals, even some rabbits, resist inoculation with the 

 freshest tuberculous material. There 'is, in other words, 

 a predisposition of the animal an adaptation of his tis- 

 sues favorable to the growth of this organism. The palm- 

 tree cannot grow in Greenland ; the oak does not flour- 

 ish in the desert ; the bacillus anthracis and the bacillus 

 tuberculosis rarely grow in the body of a dog. And 

 it may not be forgotten in the excitement over Koch's 

 discovery, that there remains much to be done in deter- 

 mining the nature of this predisposition of the animal 

 soil to the growth of the tuberculous plant. Thus far we 

 are utterly in the dark. Dr. Formad thinks he discovers 

 a ray of light issuing from certain narrow lymph-spaces. 

 If he will prove what he asserts, he will have made a 

 valuable anatomical contribution ; yet when we remem- 

 ber that rabbits and guinea-pigs are peculiarly susceptible 

 not only to tuberculosis but also to anthrax, and that cats 

 and dogs are as markedly insusceptible to the one disease 

 as to the other, it becomes evident that there must be some 

 factor in the common predisposition to both diseases alike, 

 which is not visible in the field of the microscope. 



Indeed, with all due honor to Koch, and admiration for 

 the most brilliant of experimental researches, we must ad- 

 mit that the discovery of the bacillus has chiefly an ana- 

 tomical value : it localizes in this organism the infectious 

 principle which had long been known to exist; it enables us 

 to distinguish ante- and post-mortem infectious tuber- 

 culosis from inflammation, tubercular or other, due to 

 other causes ; but it does not as yet explain the hereditary 

 predisposition, nor why this infection occurs in one man 

 and not in another exposed to the same influences. 



A dozen questions should be considered in this con- 

 nection the etiological identity of scrofula, tuberculosis, 

 and fungus joint granulations ; the possible infection of 



