103 



and the recessiveness of albino mice, when crossed with pig- 

 ment. His graduation of pigment colors worked out in the chemi- 

 cal laboratory agree, in my opinion, with Emerson's and 

 Shull's hypostatic and epistatic grades of pigment in bean hy- 

 bridizing, and the dominant and recessive colors in swine of 

 our own mixtures. 



Men with biometrics had found little gain from outcrossing 

 corn, but the precise individual methods of Dr. Shull and Dr. 

 East in producing absolutely pure types, and crossing these, 

 have brought this grain under the general law of "magnetic 

 polarity," the out-cross rejuvenation as found in crossing in- 

 bred animals. Former experimenters had been trying to in- 

 breed hybrids (corn with hiotypes), and it was like the in- 

 breeding of the Collings nondescript short horns, not inbreeding. 



The facts found by cytologists that all animal cells from 

 Paramecium to man inclusive, and all plants above bacteria 

 contain chromosomes ; that they show precise division and re- 

 duction of these at prefertilization, and an exact fixed number 

 in all germ and somatic cells of any particular variety of plant 

 or animal ; and that they constitute a mode of reproduction of 

 these chromosomes, has led us to offer a theory, which I gave 

 at Omaha. This tries to account for the mutability and varietal 

 changes of organisms by explaining the chemical and miscropical 

 action of the finer details of these organisms. Unless we can 

 guess the specific units that make and regulate life, we will 

 be hardly able to make and control it to our own particular 

 fancy. The chemist and physicist have found usually that what 

 nature can do man may also accomplish when he learns how 

 she has done it. That she has and is doing things in the lines 

 of mutability in life we have abundant proof. 



When we had apparently found to our satisfaction that the 

 chromosomes are the builders of the cells, then we asked how 

 they do it. And this I will try to tell you, accepting the hypo- 

 thesis that the chromosomes are bacterial catalytic entities, and act 

 on the blood or lymph of animals and the cell sap of plants, 

 analysing and synthesizing the chemical cytoplasm of the cells, as 

 their kindred the bacteria work chemical change in a jar of 



