^24 LECTURE XX. 



at once in the shape of a granule. As soon as it has 

 once attained a certain size, as soon as the generation of 

 new corpuscles which develop themselves out of the old 

 histological elements by a continual succession of divi- 

 sions, at last lie so close to one another as to cause a 

 mutual arrest of development, gradually to induce the 

 disappearance of the vessels of the tubercle, and thereby 

 to cut off their own supplies, then they begin to break up, 

 they die away and nothing remains behind but debris- 

 shrunken, disintegrated, cheesy material. 



The cheesy transformation is the regular termination 

 of tubercle, but, on the one hand, it is not the necessary 

 " one, inasmuch as there are rare cases, in which tubercles, 

 in consequence of their undergoing a complete fatty me- 

 tamorphosis, become capable of reabsorption ; and, on 

 the other hand, the same cheesy metamorphosis befalls 

 other kinds of cellular new-formations ; for pus may be- 

 come cheesy, and likewise cancer and sarcoma. This 

 metamorphosis, therefore, being common to more than 

 one formation, cannot well be set down as a criterion for 

 the diagnosis of any particular structure, such as tuber- 

 cle ; on the contrary, there are certain stages in its re- 

 trograde metamorphosis, where one cannot help confess- 

 ing that it is not always possible to come to a decision. 

 If a lung be laid before you with cheesy masses scattered 

 through it, and you are asked if that be tubercle or no, 

 you will frequently be unable to say with certainty what 

 the individual masses originally were. There are periods 

 in the course of development, when that which is inflam- 

 matory and that which is tuberculous can with precision 

 "be distinguished from one another ; but, at last, there 

 comes a time, when both products become confounded, 

 and whon, if one does not know how the whole arose, no 

 opinion can any longer be formed as to what its nature 

 is. In the midst of cancerous masses also cheesy spots 



