AVIAN TUBERCULOSIS. — EXPERIMENTAL STUDY. 553 



that mammalian tuberculosis can only be transmitted to birds by 

 special methods. We were therefore led to inquire what becomes 

 of the bacillus when introduced into the bodies of birds. M. Martin 

 first commenced the study of this question. He collected blood 

 from a certain number of fowls which he had intra-peritoneally 

 injected with human tuberculosis, and with it he inoculated guinea- 

 pigs. The results were extremely variable : sometimes blood from 

 fowls inoculated three months before did not appear virulent ; some- 

 times blood from birds inoculated six or even seven months before trans- 

 mitted tuberculosis. We again took up the question, but thought it 

 better to utilise the liver instead of the blood, as the microbes become 

 localised in the viscera. Our experiments gave the following results : 

 — Fragments of liver from a fowl inoculated twenty-four days before 

 transmitted tuberculosis to the guinea-pig ; fragments of the same 

 organ injected into other guinea-pigs seventj^-two, eighty-three, and 

 211 days after the primary inoculation, produced no appreciable 

 result. 



Thus a month after inoculation with human tuberculosis the bacilli 

 still persisted in the fowl's organism ; at this time they seem to betray 

 their presence by certain morbid reactions ; the fowls often become ill 

 towards the end of the first or commencement of the second month 

 after inoculation ; this fact had not escaped M. Martin, two of whose 

 fowls had died on the forty-seventh and forty-eighth day, though the 

 autopsy was negative. Now it was precisely about this time that we 

 noted visceral tuberculosis (as shown in the table below, which gives 

 the results of our experiments). 



Results. 



Negative. Positive. 



^ Between the nth and 31st days . • 5 • 5 • — 



Animals killed < Between the 35th and 59th days . 7 . 3 . 4 



( Between the 62nd and 266th days .27 . 27 . — 



Total 39 • 35 ■ 4 



Speaking generally, there was no tuberculosis before the thirty-fifth 

 or after the fifty-ninth day.* 



The question may therefore arise whether, towards the second 

 month after inoculation, lesions may not be produced, which though 

 in most cases only appreciable on microscopic examination, would 

 nevertheless explain the symptoms shown. Histological examination, 

 carried out in one case, did not support this hj'pothesis. The liver of 



* The fowl to which tuberculosis of human origin was transmitted after passage through 

 other fowls forms an exception ; in this case the virus may have .undergone modification by 

 passage through the previous birds. 



