"We do not know what life is, but we do know that life is certainly a physical property, a behavior of a colloidal miscella [grain] of a particular constitution. In order to study this constitution, this behavior, we must necessarily turn to the smallest particle of autonomous living matter, where life presents itself in its most elementary form, where the complexity of the vital phenomena is least extensive. This infinitely small being which it is necessary to study is, therefore a protobe [protos=first, bios= life] and to be even more specific, it is that one which can most readily be observed, the bacteriophage." The quotation is from a new book, The Bacteriophage and Its Behavior, by F. d'Herelle, M. D.* (Williams & Wilkins—$8.00). Dr. d'Herelle did not set out, as did Dr. Crile, to explain the nature of life or of death. His chief interest has been with diseases and their causes. He has dealt with what once was considered the lowest form of life— bacteria. He has ended by hypothesizing an even lower form, the protobe, which is neither animal nor vegetable,—simply something living. One type of protobe, the bacteriophage, he has made his peculiar study. He has found that it is the scourge to bacteria, which in turn cause disease in man. Just as almost every disease has some causative species or strain of bacteria, just so every kind of bacteria has a bacteriophage which kills it. He has not seen these bacteriophages. But he has measured them. The diameter of each one is between 20 and 30 millicrons or about one-billionth of an inch.† Also, he has seen how they destroy a bacterium. One or more bacteriophages, of the kind peculiar to the bacterium under study, penetrate the body of the germ. There they breed until they number some 18, when they become too many for the bacterium to contain any longer. It explodes into floccules, minute yet visible below the microscope lens. These floccules quickly dissolve.
This reproduction of bacteriophages at the expense of their bacterial hosts is now termed bacteriophagy. It is a disease of bacteria.
If physicians could make bacteria sick unto death, they would have one more implement in their armentarium of cures. Bacteriophagy has proved effective against some two dozen bacterial species.