634 BACTERIAL DISEASES OF PLANTS 



Of the sciences, the higher mathematics would seem to be 

 of least use to the experimental pathologist, and yet I may be 

 wrong in this judgment. Certainly the end of all experimenting is 

 to be able to express one's data in plots and curves, but biology 

 is a very complex subject, too complex apparently for any mathe- 

 matician to understand, and biologists, for the most part, are 

 very far from being able to express themselves after the manner 

 of mathematicians, however desirable it might be. Their 

 language and ours are unlike almost to mutual exclusion. If, 

 then, you are only an average biologist do not spend several 

 years on the higher mathematics, because in the end you will 

 be only an indifferent mathematician, a plodder and a grubber 

 like the rest of us, not a member of the great race. When, 

 as a student, I lamented to Harrington, the astronomer, my lack 

 of proficiency in the higher mathematics, he said: "You have 

 not cut as much underbrush in this direction, that is all." But 

 I am sure the defect lies deeper, viz., in a type of mind, and one 

 very common among biologists. The case is quite different, 

 however, if your liking for mathematics is second only to your 

 love of biology. Then you may study it as long as you feel 

 inclined. You will be a kind of a white blackbird among your 

 fellow biologists but this need not disturb you, since you will be 

 able to do some things which they cannot do. 



Of sciences which are closer to the pathologist I may mention 

 experimental physics (especially those branches of it dealing with 

 heat, electricity, hydrostatics, surface tension, viscosity, etc.) 

 and chemistry, of which he cannot have too much. Bio-chemis- 

 try in particular will be of service to him at every turn. He 

 cannot do without it unless he can arrange to work jointly with 

 some chemist and even then he should not be content simply to 

 look over the fence. The type of chemistry the pathologist 

 should cultivate is that which deals with organic compounds 

 such as his parasites produce or attack, and the problems con- 

 nected with which he will have to face. I mean the chemistry 

 of starches, sugars, celluloses, pectoses, tannins, acids, aldehyds, 

 amino acids, glucosides, enzymes, ethers, esters, and the like. 

 The pathology of the future lies right in the midst of these things 

 and more and more the pathologist must be a chemist if he 

 would succeed in a large way. 



