April 1892.] THE BOTANICAL SOCIETY OF EDINBURGH. 409 



influences exerted by internal physiological conditions opera- 

 ting under the influence of varying external conditions. The 

 determination of the sex of an embryo has depended in some 

 way upon a tendency early established, through some internal 

 equilibration of the forces of growth in response to outer con- 

 ditions of nutrition, &c." (p. 120). A male cell is defined as 

 a cell with a tendency towards a preponderance of chromatin, 

 and a female cell as one with a tendency towards a prepon- 

 derance of cytoplasm (p. 121), and " the female individual 

 may therefore be regarded in the light of a male organism, 

 in which the excessive tendency to sporulation has been 

 repressed or retarded " (p. 148). 



We may ask, justly, why should Schizomycetes be con- 

 sidered the most primitive organisms, simply because of 

 their small size and flagella ? The Schizomycetes are con- 

 sidered, and, I believe justly, to be degraded forms of Algte, 

 or of Fungi ; and how as regards the flagella, which certainly 

 do not consist of chromatin material identical to that found 

 in the body of the respective individuals ? Yet the author 

 says, " that the growth of the lowest forms of living beings 

 is effected in the main, or ends, principally in the production 

 of a single kind of living matter " (p. 153). To call the 

 chromatin " the most primitive plasma," and " the male 

 plasma," is also erroneous, for the author states himself 

 (p. 145), that " there is the best evidence that the cyto- 

 plasm is the real agent in the production of the nucleoplasm ; 

 the latter grows, as we know, at the expense of the former." 

 In this sentence, as in many others (p. 143), the term 

 nucleoplasm has been used as synonymous with the term 

 chromatin. Chromatin can, however, not be both the most 

 primitive substance and be developed at the same time out 

 of cytoplasm, and for this reason it is wrong to speak of 

 male chromatin as being the primary, and female cytoplasm 

 the secondary, constituent of a cell. To be consequent, the 

 author should have stated that the female element, or cyto- 

 plasm, was the older, and the male element, or chromatin, 

 the younger plasm. 



I myself hold that assimilation is the only factor in deter- 

 mining sex, as Claude Bernard stated long ago, but do not 

 believe it consistent with fact that female cells are nothing 

 but retarded male cells, or cells which would have broken 



TRANS. EOT. SOC. EDIX. VOL. XIX. 2 H 



