CLASSIFICATION OF NEOPLASMS. 39 



meiits be traced back to some model which had pre- 

 viously maintained an independent existence in the 

 economy. 



The classification of pathological new formations, of 

 genuine neoplasms, was formerly by most observers 

 attempted to be based upon their different degrees of 

 vascularity. If you examine the different treatises which 

 appeared upon this subject up to the time of the cell- 

 theory, you will find that the question of organization 

 was always decided by that of vascularity. Every part 

 which contained vessels was regarded as organized, and 

 every part as unorganized which was destitute of ves- 

 sels. But this, according to present notions, is an 

 incorrect view of the matter, inasmuch as we have also 

 physiological tissues without vessels, as for example, 

 cartilage. 



But at a time when the more minute elements of 

 tissues were at most only known as globules, and when 

 very different virtues were attributed to these globules, 

 it was quite excusable that everything should be referred 

 to the vessels, particularly after the comparison John 

 Hunter made between pathological new formations and 

 the development of the chick in the egg, when he endea- 

 voured to show that, just as the punctum saliens in the 

 hen's egg constitutes the first phenomenon of life, the 

 vessels also where the first things to show themselves in 

 pathological formations. You no doubt still remember 

 how several "parasitical" new formations were de- 

 scribed by Rust and Kluge as provided with an inde- 

 pendent vascular system, which without having any 

 connection with the old vessels, developed itself quite 

 independently, as is the case in the chick. Many 

 attempts had indeed been made even before this to 

 refer the apparently so irregular forms of new formations 

 to physiological paradigms, and herein essential service 



