HEREDITY OF ACQUIRED CHARACTERS CUEISTOT. 343 



or else of synapsis. Now it is known that among the mammals 

 these phenomena take place in the embryo, and that the adult has 

 only ovocytes which grow slowly and unequally and come succes- 

 sively to maturity. We have a means of verifying this subsidiary 

 hypothesis, for adult males present all phases of spermatogenesis, 

 from spermatogonia to spermatozoid. By injecting anticrystalline 

 serum in males, their sexual cells should be affected at the sensitive 

 stage, and, mated later with normal females, they should transmit 

 the anomaly, which would be visible only among their grandchildren. 

 It is a crucial experiment ; I do not see that Guyer and Smith have 

 tried it. 



It would be better, in order to simplify the experiment, to use 

 rot merely the hen as the source of crystallolysin, but rather the 

 rabbit itself, in this way not introducing the foreign factor, the hen 

 serum. However, Guyer has recently succeeded in obtaining a 

 young rabbit with two defective eyes by injecting several times in 

 the normal mother crushed crystalline lens of rabbit before she was 

 with young and during her gestation. A rabbit can, then, form a 

 crystallolysin as efficacious for the rabbit as that produced by a 

 foreign species. 



Thus we have been led to admit, in order to interpret the results 

 of Guyer and Smith, that the crystalline lens has some representa- 

 tion (it matters little how we understand the word and the thing) in 

 the germinal cells, since the specific antibody acts upon them specifi- 

 cally. Now, the crystalline is indeed the last organ which we 

 should expect to see represented in the sexual elements. Beautiful 

 researches conducted, it is true, on fish and batrachians tend to lead 

 us to consider 9 the crystalline lens as the epigenetic organ par 

 excellence, as a reaction of the epidermis in contact with or in the 

 vicinity of the optic cup; when the latter comes in contact with 

 the epidermis at any point whatever (abdomen, mouth, dorsal face, 

 etc.), it develops a crystallinian thickening. It is not necessary, 

 then, to believe that the crystalline is " represented " directly in the 

 hereditary patrimony, since it is enough that the optic cup be 

 represented in order that there may be formation of crystalline. 

 This is, however, only a difficulty. 



Let us come back to acquired characters. The experiments of 

 Guyer and Smith, while admitting that they should be confirmed 

 in fact and interpretation, will permit us to accept henceforth the 

 heredity of characters acquired under the influence of the great 

 general factors of the medium. At the same time that these pro- 

 duce their more or less adaptive effect on certain tissues of the 



• See Werber, Critical notes on the present state of the lens problem, Biol. Bull., vol. 

 XXXIV, 1918, p. 219. Fessler, Zur Entwicklungsmechanik <3es Auges, Archiv. fur Entw, 

 der Org., vol. XLVI, 1920, p. 169. 



