686 SCIENCE PROGRESS 



of exhibiting a particular phenomenon. There seems nothing 

 improbable in the supposition that this potentiality — which is 

 retained by the gametogenic cells through many generations to 

 be exhibited only upon a particular occasion and probably only 

 under certain conditions — may be retained by other cells of the 

 body, though no physiological set of conditions can appear to 

 bring it into action. Such a supposition implies no more than 

 that in all the cells of the body in which differentiation has not 

 advanced to a stage which precludes further multiplication the 

 potentiality is retained of going so far on the road towards the pro- 

 duction of gametes as is involved in the meiotic phase. When this 

 occurs in gametogenic tissue, that is physiologically, specialisa- 

 tion follows and the result is the production and throwing off of 

 gametes. In other cells, however, though they go through the 

 meiotic phase after passing out of somatic co-ordination as the 

 result of chronic irritation or some other unknown stimuli, the 

 environment is not such as allows of the production of gametes 

 and the result is the production of a group of cells living in 

 a parasitic manner upon the parent organism, cells which 

 multiply indefinitely and eventually destroy their host. 



As the gametogenic cells pass out of somatic co-ordination, so 

 do the cells which form cancer ; living as they do in a parasitic 

 manner upon the parent organism, both must be regarded in a 

 limited sense as independent individuals. The malignancy and 

 the meiotic phenomena of cancer are both caused apparently by 

 the cells having passed out of somatic co-ordination. It is not 

 suggested that the malignancy is due to the cells having passed 

 through the meiotic phase. 



Many writers appear to think that the interpretation of this 

 phenomenon involves the belief that the cells of cancer are of 

 the same nature as the gametogenic cells. The mere fact that 

 the term " gametoid " 1 is applied to the cancer cells shows that 

 this is not the case. Meiosis (reduction) is obviously a very 

 primitive phenomenon. It occurs universally among plants and 

 animals in the production of gametes and in both gametogenic 

 and cancer or gametoid cells it follows upon passing out of 

 somatic co-ordination. As it does not appear among the cells 

 which are in somatic co-ordination, there can be no suggestion 

 that meiosis is the cause of this aberrance. 



1 Farmer, Moore and Walker, 1903, op. cit. 



