46 



There i^^ every rea^-on to suppose, for example, that the action of light 

 is not the same under all the conditions of temperatnv.?, A\hich ob- 

 tained during these experiments. Here again, however, we ai'e con- 

 fronted by the unknown; because, in order to draw from these 

 researches the consequences which might flow from them it would be 

 necessary to know precisely the thermic conditions favorable to the 

 germination of each species. Unfortunately this is a very important 

 gap to be still filled up, as the work accomplished in this direction 

 gives only approximate results limited to a very small number of 

 different kinds of seeds. On the other hand, looking to facts of 

 another order, mentioned further on in this work, we think that we 

 may be allowed to suppose that the influence of light can only be 

 favorable to germination when it acts at temperatures below that 

 which is most favorable to germination. A considerable number of 

 observations already cited would seem to be in accord with this view 

 of the subject. But unfortlmately the many contradictions that we 

 observed in our results do not allow us to accept this opinion as based 

 upon a solid foundation. 



Pauchon then goes on as follows : 



Another reason, however, induces me to admit, only with many 

 reserves, the results of experiments whose critical epoch is the visible 

 development of the embryo. A method based on this special observa- 

 tion does not appear to me capable of furnishing a really scientific 

 basis for the determination of the question before us. The process of 

 germination is not, in reality, as simple a phenomenon as the greater 

 number of botanists, perhaps too easily, take for granted. Its com- 

 l^lexity is even so great that one can not judge of the actual develop- 

 ment of the germ of the plant and of the degree of its physiological 

 activity by the external characters observable by the eye, such as the 

 bursting of the spermoderm and the more or less rapid protrusion 

 of the radicle. I do not hesitate to say, according to observations 

 frequently repeated, that this is an empirical process and entirely 

 deceptive in the particular case that we are dealing with. Although 

 it may be capable of furnishing valuable results when av(> wish to 

 judge of the influence of some one of the fundamental conditions of 

 germination, it becomes utterly insufficient when it is a question of 

 observing the more delicate and fugitive influences, such as that of 

 light. I have, in fact, in the course of chemical researches, given in 

 the next chapter, demonstrated that for the same stage of apparent 

 development the absorption of oxygen by the seeds in the process, oi 

 germination varies to a large extent Avith the temperature, and has 

 no relation to the external growth of the embryo. It is, howevei'. 

 not surprising that the development of the embryo continues in the 

 interior of the seed for a much longer time in one seed tlian in 

 another of identical appearance; the unknown and variable relation 

 between the reserved nutrition and the rudimentary vegetable is 

 probably the explanation of these hitherto unex])lained peculiarities. 



Although the researches given in tl-ris chapter do not give any posi- 

 tive result on the subject of my work, I have preserved them .nid pub 



