226 COOK 



Regarding the real natures or details of the processes of trans- 

 mission and expression, we know as little as we did of inheri- 

 tance, but it is a measure of progress to learn that there are two 

 factors instead of one. Transmission inheritance is not recip- 

 rocal or alternative like expression inheritance. 



The relations which may be supposed to determine the char- 

 acters of conjugate organisms are obviously very different from 

 those which determine the characters of the gametes. The 

 characters of a conjugate and those of the gametes it produces 

 may both be results of relations assumed b}'^ the same original 

 parent gametes, but the relations in the two cases are entirely 

 distinct, as the results themselves testify. The conjugate results 

 are large, highly complex organisms, while the exjugate results 

 are minute, simple gametes. 



The older interpretation of the facts of descent led us to 

 reckon the gametes as products of the bodies of the plants or 

 animals, minute propagating particles qualified to faithfully 

 reproduce the same kind of a body, unless this were prevented 

 by external circumstances. The present interpretation recog- 

 nizes that new gametes are not so much the offspring of the con- 

 jugate body as of the gametes from which the body was formed. 

 The gamete-producing cells are often related to the cells of 

 the body of the "parent organism" only as they represent 

 common offspring of the original gamete-pair, and even then 

 there is the very serious difference that the body-cells, being 

 devoted to vegetative purposes onl}^ do not complete conjuga- 

 tion at all. The gamete cells do not correspond directly to any 

 of the body cells because they have passed through mitapsis 

 and belong already to a new generation, a new section of the 

 network of descent. 



Conjugate organisms are built up at the knots or junctions of 

 the networks of descent. In the lower groups exjugate cells 

 build up organisms on the threads of the network, between the 

 knots. Conjugate organisms can be thought of as thickening 

 the knots of the network, exjugate organism as thickening the 

 threads. But in both cases vegetative specialization may bring 

 a loss of reproductive powers and exclude the specialized cells 

 from any direct representation in the subsequent network of 



