360 THE BACTERIOPHAGE AND ITS BEHAVIOR 



of the beings which present the same characteristics is rendered the more 

 probable by the facts disclosed in connection with the bacteriophage. 

 These infravisible beings have been termed "invisible viruses," ''ultra- 

 viruses," "ultramicrobes," etc. This does not give them a name, for 

 these terms are simply qualifying terms, designating their state of 

 invisibihty. 



In presenting the demonstration of the living nature of the bacterio- 

 phage, I have proposed to designate this group of living "micellar" 

 beings by the name Protobes,^^^ a term which I have apphed to the 

 bacteriophage.* 



2. ASSIMILATION BY THE PROTOBES 



Here we step into the unknown. For the mere fact of knowing that 

 a being assimilates reveals nothing as to the "mechanism" through which 

 it assimilates. We know that there is a transformation of matter; that 

 the bacteriophage protobe transforms "bacterium substance" into 

 "bacteriophage substance." Let us see if by examination of the known 

 facts we may gain some insight into the manner in which this trans- 

 formation is effected. 



In the first place, it seems to have been demonstrated that the me- 

 taboUsm of the parasitic protobes is limited to living matter; that this 

 is the only material which they can utihze for their development. 



The chemical transformation which the hving matter of the prey 

 undergoes, whether this be a bacterium in the case of the bacterio- 

 phage, a vegetable cell in the case of the mosaic protobe, the animal cell 

 in the case of the protobe of variola, must be very extensive, for the 

 antigenic properties are changed. It is for this reason that the in- 

 jection of an animal with the "bacteriophage protobe substance" 

 causes the appearance in the serum of this animal of an antibacterio- 

 phagic property, a property which is not manifested when the animal 

 is injected with "bacterium substance." 



On the other hand, can the assimilative process be as far-reaching in 

 these rudimentary beings as it is in beings more highly organized and 

 equipped with a digestive tract? To approach this point let us consider 

 how assimilation is effected in those beings representing the next higher 

 step in the scale, — the bacteria. It may be possible to apply the facts 



* These beings, certainly the most simple that exist, are placed at the very- 

 bottom of the classification scheme as the "first living beings," and this is what 

 the term Protobe means. Above the Protobes {irporos /3tos) come the bacteria, 

 the Microbes (jmlxpos Plos). 



