MORBID GROWTH IN GENERAL. 69 



"Wounds,"* he developed the idea that an effusion of lymph was 

 the neeessaiy starting-point of all new growth. The plastic 

 quality was regarded by him as a force inherent in the effused 

 material, prompting it to the production of every sort of tissue 

 from its own substance. An independent vascular apparatus is 

 always the first thing to be developed ; this is responsible for 

 every farther step in the process ; it furnishes fresh supplies of 

 plastic lymph, and so on. Through conceptions of this order — 

 which rested, by the way, on a basis of the most careful observa- 

 tion — we detect a glimmering conviction that the growth is some- 

 thing foreign to the organism, something introduced into it from 

 without — a parasite, to use an extreme term. Hunter was led 

 to this conclusion chiefly by comparing morbid growth with the 

 development of the chick in the Qgg. He knew nothing of the 

 cell, and regarded the j^^tnctum saliens as the starting-point of all 

 development. 



The discovery of the cell, speedily followed by the recogni- 

 tion of cells in the embryo before the existence of a heart, 

 necessarily exerted a modifying influence upon Hunter's theory. 

 The development of the vascular system fell back at once into 

 a secondary place ; and when it became certain that, apart from 

 the first mapping out of the circulatory system, every develop- 

 ment of new vessels was only an extension of the already 

 existing system of canals, the theory of an "independent vascu- 

 larity" of new growths fell to the ground, carrying with it in its 

 fall a good part of their personal individuality. The question 

 was shifted from " How do new growths originate?" to " What 

 is the origin of cells?" The alternative which had presented 

 itself in the case of the vessels recurred in the question as newly- 

 formulated. Theories were at once constructed, based on the 

 spontaneous generation of the cell. Plastic lymph, or rather the 

 " plastic quality" of lymph, continued as before to be regarded as 

 the formative cause in the irenesis of tissues. It now received 

 the name of cytoblastema, or more briefly blastema. 



A full discussion of one or other of these theories would lead 

 nie too far. Suffice it therefore to say, that the doctrine was 

 at first applied very unconditionally. Blastema, wherever found, 

 was supposed to consist of an exudation of the jylasnia sanguinis. 



* Translated into German by Hehenstreit in 1797. Published by 

 Hunter in 1703. Palmer's edition, vol. iii. 



