28 ARTIFICIAL PRODUCTION OF TUBERCLE. 



Hospital, that the removal of diseased bone' prevents the formation of tubercle 

 in predisposed subjects.^ 



Although, as I have now stated, the evidence, as it at present stands, 

 seems to show that these effects are most readily produced by septic agencies, 

 it may yet appear not impossible that ordinary irritants may, under special 

 circumstances, have the power of exciting locally that peculiar development 

 of quasi-lymphatic tissues which, if not the essential character of tuberculosis, 

 is yet its most constant and striking feature/ This theory, if true, would 

 seem to explain many cases where catarrhal inflammation of the bronchi 

 is followed by tubercular processes in the lungs, owing to the irritation being 

 propagated to the lymphatic structures in these organs — events which have 

 hitherto, in spite of very distinct evidence to this effect, been excluded by 

 many writers from the causative influences of this disease, mainly through 

 the views so largely held regarding its specific character. 



There appears, however, to be another element necessary in these cases, 

 ■and that is a constitutional state predisposing to such effects. This is well 

 illustrated in the different susceptibility of the guinea-pig and the rabbit ; the 

 former being much more prone to be thus affected by these agencies than the 

 latter. In fact, I think it probable that it is to this cause that the failure of 

 M. Villemin's experiments with other materials than tubercle, and which were 

 conducted upon rabbits, is to be attributed. 



I think, however, it requires to be stated, that neither guinea-pigs nor 

 rabbits are naturally by any means specially prone to tubercle. Zoologists and 

 comparative anatomists, of whom I have asked the question, have not noticed 

 this disease amongst them, except as a consequence of injuries. They have 

 long been the subject of physiological experiment, but tubercle has not been 

 noticed among their common diseases. M. Villemin's experiments also showed 

 that only the inoculated rabbits thus suffered. I have kept large numbers of 

 guinea-pigs during the last six months, and many rabbits ; but not one has 

 died tuberculous, except those inoculated. As a further test, I killed six non- 

 inoculated guinea-pigs, taken without selection ; and not one presented a trace 



1 Lancet, 1865, i. 60. cular disease, -wliich he considered was produced 

 * My attention has, since the delivery of this by the infection of the blood. See also Von 

 lecture, been called to some earlier observations of Troeltsch, Anatomie des Ohres., 18G1, p. 72 ; and 

 Dr. Von Troeltsch on this subject. In Virchow's Lehrbuch der OhrenheUkunde, 3d edition, 1867, 

 Archiv, vol. xvii. 1859, pp. Gl-77, he has related p. 337. Confirmatory cases have also been pub- 

 three cases of acute miliary tuberculosis consecutive lished by Schwartze, Archiv fiir Ohrenheilkunde, 

 to long standing disease of the bones of the ear ; ii. 280. 

 and expressed his belief that the suppurative ^ See Appendix, p. 31. 

 action thus induced was the cause of the tuber- 



