376 THE BACTERIOPHAGE AND ITS BEHAVIOR 



It was only when they attacked the infinitely small particles of chemical 

 substances, when they studied the infravisible, that the day commenced 

 to dawn. The meaning is clear. Surely it is not through studying 

 visible organisms, complex ones, that biologists will reach the solution 

 to then- fundamental problems, for with such the investigator finds 

 himself surrounded by a multiplicity of diverse factors, which by their 

 very number and by their complexity effectively prevent advance into 

 the unknown. The physicists have blazed the trail. 



Here, as in the study of matter, it is necessary to approach the problem 

 from the bottom. We do not know what Hfe is, but we do know that 

 life is certainly a physical property, a behavior of a colloidal micella of a 

 particular constitution. In order to study this constitution, this be- 

 havior, we must necessarily turn to the smallest possible particle of 

 autonomous living matter, where life presents itself in its most ele- 

 mentary form, where the complexity of the vital phenomena is least 

 extensive. This infinitely small living being which it is necessary to 

 study is, therefore, a protobe, and to be even more specific, it is that one 

 which can most readily be observed, the bacteriophage. 



RESUME 



The living state can only depend upon one of the two following con- 

 ditions: either life results from an organization, or it results from a 

 physico-chemical state of matter. 



Up to the present time the first theory, the cellular theory, has been 

 almost universally accepted. 



The fact that the bacteriophage corpuscle has been demonstrated 

 to be a simple protein micella, and that it is a living being, shows that 

 the cellular concept of life is erroneous. Of necessity, then, the second 

 alternative must be true. Life results from a particular physico- 

 chemical state of the protein micella. 



With cellular beings, in particular with the metazoa provided with 

 a digestive apparatus, assimilation is complete. That is, the substance 

 of the food is transformed into substance identical with that of the being 

 which assimilates. With the protobes, and also with the bacteria, 

 experiment demonstrates that assimilation is incomplete. Although 

 the substance of these beings is essentially different from that of the 

 foodstuffs consumed, nevertheless, it varies with the nature of the food, 

 as is proved by the variation in antigenic properties. 



As a result of these variations, which are common to the protobes 

 and to the microbes, — to bacteria at least, — there occurs a great variabil- 



