ARTIFICIAL PRODUCTION OF TUBERCLE. 29 



arises, whether this be not the starting-point of the whole process. If, 

 however, the character of these granulations be doubted, still the affection 

 of the lymphatic glands in their neighbourhood has so strong a resemblance 

 to that which occurs in these structures, when secondary to tubercle in other 

 parts, that it would appear either to confirm the tuberculous character of the 

 granulations, or to carry the point of origin of the tubercular infection 

 only one stage further forward. 



One fact also deserves to be brought 9^pecially into prominence; viz., 

 that the effects of infection are more certainiy produced by the inoculation 

 of tubercle than by that of other substances. The whole series of primary 

 inoculations of this nature succeeded when the animals lived long enough 

 to allow of the affection of their internal organs ; and the series of twelve 

 re-inoculations of tubercle artificially produced had the same results. It does 

 not, however, appear that the mode in which tubercle of the latter class had 

 originated produced any difference in the certainty of the effect of the re- 

 inoculation. Tubercle developed by the inoculation of putrid muscle 

 reproduced tubercle with the same certainty as that originating from the 

 inoculation of the grey granulations. 



Whether any direct effect can, in virtue of this superior infecting property, 

 be ascribed to tubercle, must remain, I think, an open question ; but it does 

 not appear impossible that it may have in some way the power, when thus 

 introduced, of directly propagating itself, similar to that observed in actual 

 practice, when there is great probability that the multiplicity of the affection 

 may be due to secondary infection of distant organs from that primarily 

 implicated. Another point to be noticed with regard to tubercle — though 

 this possibly may not prove very material — is, that it is capable of thus 

 producing infection when inoculated in a perfectly fresh state from an animal 

 just killed. It should also, however, be remembered, that the low forms of 

 pneumonia, which were formerly classed with the tubercular products in the 

 lung, appear to possess this infecting property in an equally high degree. 



Whether the infection of the system is by chemical or by mechanical means, 

 whether it is produced by fluids or solids, by cell-forms, " germinal matter," 

 or amorphous material, must remain, I think, a matter of hypothesis, in which 

 the minds of individual observers will incline to one view or the other, 

 according to the bent of their special pathological theories, but which has not 

 as yet received any absolutely satisfactory elucidation. An experiment of 

 Dr. Waldenburg's, in relation to this question, is, however, deserving of 

 mention. He has found that colouring matters introduced under the skin, 

 together with the infecting material, are reproduced in the gro-niihs of new 



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