APPENDIX. ' 31 



APPENDIX. 



Note to P. 28. 



Since tlie lecture was delivered, I have had proof that even simpler irritants may serve 

 as the starting-point of the tubercular process in the guinea-pig. Of twenty-four of these' 

 animals (not included in the preceding numbers), in whom, for purposes of identification in 

 another experiment, I had inserted a small piece of silver suture wire in the nucha, three 

 became tuberculous. The appearances around the seat of injury, together with the implica- 

 tion of the neighbouring lymphatics, left no doubt that the origin of the disease was from 

 this local cause. The escape of all the other animals points to the slighter efficacy of such 

 a simple irritant in producing tubercle, as compared with those previously employed. Access 

 of air to the subcutaneous tissue was of course possible, and thus the question of a " septic " 

 agency must still be entertained ; but the possibility nevertheless remains, whether this effect 

 may not be produced by simpler causes of irritation. 



K. CLAY, SONS, AND TAYLUIi, rUINTEES, lil.KAl) STl'.EET HILL. 



