42 TEE POPULAR SCIENCE MONTHLY 



I wish to study the cryptogamic diseases of my wild wheat in order to try to 

 discover if among them there are any peculiar to wheat in other regions and 

 which here would attack other plants. We could then say this or that cryptogam 

 was carried by cereals and would be found in the same situation in relation to 

 wheat, as certain phanerogamic satellites such as Lolium temulentum, Githago 

 segetum, etc., etc. 



I am sending with this letter a small photograph showing our workmen 

 sowing Triticum dicoccoides with a drill. I shall not conceal from you that I am 

 very proud that when for the first time since prehistoric times man has again 

 tried sowing the prototype of wheat, this work has fallen to Jews (escaped from 

 the ignoble massacres of Russia), Jewish teams working on Jewish ground, the 

 historic cradle of the race. 



Yours sincerely, 



A. Aaeonsohn 



You perceive - the wide field which this discovery has opened up. 

 The utilization for new needs of new races of wheat to be segregated 

 from this wild material, that is, from the polymorphic plant popula- 

 tions of the hills of Judea, the extension of the cultivation of cereals 

 to arid regions or mountainous zones, where it has hitherto not been 

 possible. 



But there is more than that. We possess now, and Mr. Aaronsohn 

 alludes to it in his letter, a second method of improving wheat by the 

 method of selection, growing pure races from single seeds. 



We can, by crossing, create new races and in this domain modern 

 methods have a startling precision. They say that the man who sud- 

 denly had a new world revealed to him by the microscope lost his 

 reason. To-day, placed in the presence of the facts brought to light 

 by modern biological analysis, we can see in our minds an infinite line 

 of discoveries which were not even suspected by the generations pre- 

 ceding us. 



Here, in a few words, are the results already obtained: 



They lead us to suppose the existence of essential representative 

 particles within the germ cells of plants. These particles may be com- 

 pared to the atoms which chemists suppose to exist in the inanimate 

 world. These are the biological elements, the " organic corpuscles " 

 as Buffon would have called them. We call them " gens." The body 

 of the plant with its diverse characters is then only the exterior mani- 

 festation of these " determinants." We suppose, then, that each char- 

 acter manifested is determined by a " gen," a " determinant." To 

 constitute an organism with its characters there must be an association 

 of gens. 



For the sake of similarity in studies on heredity plants belonging to 

 the same systematic grouping, the same genus or the same species, are 

 usually compared. Only the characters in which these two plants 

 differ are taken into account. For example, a race X will differ from 



