26 MENDELISM 



question has been put to me. It is said that Benjamin 

 Franklin was once asked a similar question, and he replied, 

 "What is the use of a new-born baby? " The aim of the 

 man of science is to gain knowledge of the world around 

 him, to study Nature, and learn as much as he possibly can 

 about its forces and phenomena, and he is not directly or 

 immediately concerned with the application of these facts. 

 Fortunately, I can give an answer which will be much 

 more satisfactory to utilitarians than was Benjamin 

 Franklin's. 



For a great number of years agriculturists have been 

 endeavouring to improve British Wheat. They have 

 effected an immense number of crosses, without making 

 any very substantial progress, because they have not had 

 any guiding principle or theory to work upon. Now let 

 us see what has recently been done by Prof. Biffen of 

 Cambridge working on Mendelian lines. You are aware 

 that certain kinds of wheat, including British wheat, are 

 particularly liable to a disease which destroys the grain — 

 a disease called "Rust." About ^100,000,000 worth of 

 wheat is destroyed annually. 



On the other hand, there are some kinds — mostly small- 

 eared wheats growing in America and elsewhere — which are 

 not liable to this disease. They are immune. 



It occurred to Mr. Biffen to cross these two kinds. The 

 resulting hybrids were all affected by the disease, and so 

 badly affected that he had difficulty in preserving any of the 

 trains with which to continue the experiment. Now if you 

 have quite understood what has gone before, you will at 

 once see that he had achieved a great result, for this first 

 experiment showed that the susceptibility to disease was a 

 dominant character, and the immunity, or non-liability to 

 disease, a recessive character. You can easily follow the 

 further steps of the experiment, thus — 



