488 



together or at different times, but with abnormalities on the part of 

 one, there may result a more or less rudimentay embryo, an embryoma 

 of Wilms, a tumour. 



The number of primary germ-cells is constant for the species, 

 2, 4, 8, 16, 32, 64, etc. Thus, it is 8 in the frog, 32 in the lamprey, 

 128 in the common dog-fish, etc. One must always be deducted from 

 this number to form an embryo, and the remainder migrate or wander 

 into the embryonic body to furnish the foundation of the reproductive 

 products. Apparently it never happens, that all find their way to the 

 normal position, but a percentage of them comes to lie in one or 

 other of many abnormal positions. So that, as a fact, hardly a single 

 organ of the body is free from the risk of possible "infection" by 

 such vagrant germ-cells. The aberrant germ-cells represent in fact 

 "lost germs", endowed with far greater potentialities for mischief than 

 any such hypothetical ones ever conceived of by pathologists. 



As the writer has already shown elsewhere 1 ), if such a vagrant 

 germ-cell skip the part of the cycle immediately before it, its ab- 

 normal development may lead to the pathological formation of the 

 representative of a chorion, possessed of unrestricted powers of growth 

 — a cancer. The proof of the truth of this receives the strongest 

 confirmation from the subsequent part of the work dealing with the 

 nature of tumours in general. 



The question of the treatment of cancer raises serious issues. In 

 every normal development the chorion or syncytium commences to 

 degenerate at a well-defined epoch (the "critical period" of the author). 

 Did it not do so, its further unrestricted growth would lead to a form 

 of cancer, deciduoma malignum or chorio-epithelioma. The degeneration 

 of the chorion aud with this the arrest of its growth are in all pro- 

 bability brought about by some substance, either contained within 

 the foetal allantoic placenta, or present in the blood of the foetus. 

 Just as the foetal allantoic placenta, or the foetal blood, can induce 

 the degeneration of the chorion, so it ought to be possible from allantoic 

 placenta or foetal blood of animals, such as the pig, to prepare an 

 extract, a serum, with potent workings upon the cells of cancer. 



The second and larger portion of the work treats of the nature 

 of tumours in general. In the light of embryology, especially as that 

 science is conceived of by the writer, the tumours are capable of very 

 simple explanation. Most, if not all, true tumours are but 

 bizarre pathological manifestations of some portion 



1) Lancet, June 21, 1902, p. 1758. 



