30 ARTIFICIAL PRODUCTION OF TUBERCLE. 



I would, however, finally venture to observe that I think we should be 

 cautious in drawing conclusions that the method of the production of tubercle, 

 now partially elucidated, is the sole mode of origin of this disease. 



M. Villemin's experiments have, like many others in science, led to a 

 dififerent conclusion from that which the first observer drew. These results 

 appear to me to have a wider scope and to open questions of deeper interest 

 than that of the specificity of tubercle, important as such a demonstration, 

 could it be justified by the facts, would have proved. The subject now rests on 

 a wider physiological and pathological basis respecting its nature and origin. 

 It will doubtless be still a question in some minds whether the results of these 

 experiments are truly tubercle. That question must be settled by the con- 

 currence of other observers, though already there is a wide uniformity of 

 opinion in the afiirmative on this point. Por my own part, I can only express 

 my conviction, to which I have arrived by a long and careful comparative 

 series of observations, that these growths are identical with the typical 

 forms of tubercle. 



I believe, however, that further efi'orts, which may be directed to the 

 interpretation of these results and to the explanation of the origin of tubercle 

 under these new and hitherto strange circumstances, cannot fail to be pro- 

 ductive of new truth. It may yet be long before they receive their full and 

 adequate explanation — an explanation for which further advances in anatomy 

 and in pathological physiology appear to be requisite in order to reveal 

 to us the reason for the peculiar localisation and circumscription of these 

 growths, and to explain the conditions under which they occur. It would 

 appear that but a small tract of a wide field for inquiry has as yet been opened 

 for new researches, though I feel convinced that it is one which will repay the 

 energies of the most careful and attentive observers. The explanations which 

 we may now devise to ourselves are only at present of the nature of more or 

 less tenable hypotheses. I cannot, however, but believe that the new series 

 of facts now disclosed will be proved to be no unimportant portion in the 

 phenomena which must be embraced by these hypotheses, and that in pro- 

 portion as the nature and mode of origin of tubercle are more fully explored, 

 we may, I think, indulge in the not unphilosophical hope that with the 

 discovery of its causes we may find means at least for its prevention, if not in 

 all cases for its cure. 



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