88 'DETERMINANTS' VEBSUS 



these new plants that the sexual cells are produced, which after 

 fusion grow up into a fern. Thus the life of a fern is cyclical, and 

 one of the most remarkable results of recent biological inquiry has 

 been the demonstration of the fact that the cells of the fern differ 

 from those of the prothallium in that they contain just twice as 

 many little rod-like bodies which stain with aniline dyes and have 

 been called chromosomes. In the fern and the prothallium these 

 numbers remain constant, and the reduced number in the pro- 

 thallial cell is brought back again to that of the original fern only 

 by the fusion of the sexual elements." 



" Now it has been found that in some ferns spores need not be 

 formed, but that the reduced prothallial tissue sprouts out upon 

 the fronds in little masses, while in others the same result can 

 be produced by artificial conditions, by pinning the fronds down 

 on damp earth, whereupon after a time the prothallial growth 

 spreads like a cancerous development round the edges of the 

 frond." 



" It has long been known that the cells of animals, like those 

 of plants, contain constant numbers of chromatic rods, and it is 

 further known that a similar reduction in these numbers takes 

 place regularly in the development of the sexual cells ; but what 

 has not hitherto been suspected is the fact first pointed out in 

 the paper already referred to, that the changes witnessed in the 

 development of cancerous tissue are identical with those occurring 

 in the normal sexual reduction of the tissues both of animals and 

 plants." 



" From the results of these observations, if correct, we reach, 

 in fact, the singular conclusion that a cancerous growth in man 

 is precisely similar to the abnormal production of prothallial 

 tissue on the fronds of a fern ; or, in other words, that the onset 

 of this terrible human scourge is indirectly due to some of those 

 not as yet fully understood causes which, like the tying down of 

 the frond of a fern, induce the normal tissues of the body to enter 

 on the reproductive or ' reduced' phase of its life cycle." 



One of the authors of this investigation in a later communica- 

 tion, in July last, to the Pathological Society recorded another 

 interesting fact closely related to the observations of the Russian 

 naturalist and those of Prof. Loeb. Thus C. E. Walker says in 

 reference to the observations on cancer cells, "The occurrence 



' See ' Transactions ' of the Society, Vol. LV, p. 454. 



