282 THE BACTERIOPHAGE AND ITS BEHAVIOR 



The bacteriophage corpuscle having a diameter of 20 to 30/x^t, and 

 being insoluble in water, necessarily possesses colloidal properties. 

 Within a culture medium it is a colloidal "micella" whatever may be the 

 intimate nature of the substance of which it is formed. 



The bacteriophage is either a living being or a product derived from 

 a living being (bacterium); and such being the case the ''substance" 

 of the bacteriophage corpuscle must be either of lipoid nature or of 

 protein nature.* 



If it is a lipoid it should be soluble in the solvents for these bodies, — 

 ether, chloroform, or petroleum ether. 



Kabeshima^^* has affirmed that the bacteriophage is soluble in both 

 ether and chloroform. I have shown^^^ that this is not true, for if one 

 mixes equal parts of ether and bacteriophage suspension, it is found 

 after prolonged shaking that the proportion of corpuscles present in the 

 ether and in the subjacent fluid is as 1:40,000. This clearly indicates 

 that there has been a commingling and not a dissolution, for it is only 

 necessary to shake this ether with bouillon to remove the greater part 

 of the corpuscles, and by repeating the extraction with bouillon it is 

 possible to remove them all. 



De.Poorter and Maisin^^^ have effectively answered this question of 

 ether solubility. They mixed 1 cc. of a bacteriophage suspension with 

 2 cc. of ether. Then they superimposed 10 cc. of ether, taking care 

 through all of these procedures not to wet the walls of the tube, for if 

 this is done corpuscles may remain adherent to the walls and give errone- 

 ous results. After allowing it to stand for 24 hours at laboratory 

 temperature they removed a few cubic centimeters of the supernatant 

 ether, evaporated it at a low temperature and looked for the bacterio- 

 phage in the residue. No trace of it could be found. 

 f , They performed the same experiment with petroleum ether and with 

 chloroform, with the last by first introducing 10 cc. of chloroform into a 

 burette and then a well shaken mixture of bacteriophage suspension 

 and chloroform. The results were the same; there was nothing to 

 indicate that the bacteriophage was dissolved. 



These authors concluded that the substance of the bacteriophage is 

 not a lipoid, and this being the case it follows, therefore, that the 

 bacteriophage corpuscle is made up of a protein substance. 



Wollman''^^ has stated that the bacteriophage is destroyed by tryptic 



* Glycogen occurs also in the form of colloidal granules, but the bacteriophage 

 is not glycogen, for a liquid which contains the bacteriophage, boiled after the 

 addition of a strong acid, does not reduce Fehling's solution. 



