110 THE BACTERIOPHAGE AND ITS BEHAVIOR 



Employing a less active bacteriophage, 0.1 cc. of a suspension with 

 1000 million corpuscles per cubic centimeter, added to 10 cc. of a bac- 

 terial suspension, shows very little fixation after contact for 30 minutes. 

 Even with the contacts repeated for 5 successive times, the material 

 being centrifuged between each contact and fresh organisms added 

 each time, a complete fixation is not attained. 



In brief, therefore, the course of fixation is exactly opposite to that 

 observed in the fixation of agglutinins. We must regard the fixation 

 of bacteriophage corpuscles to the bacteria as a phenomenon of col- 

 loid nature — and nothing could be more legitimate since all of the 

 reactions of living matter are colloidal reactions — and it would be 

 strange indeed if bacteriophagy formed an exception. 



It is assuredly true that as yet we do not know the intimate mecha- 

 nism of the process, yet we may unquestionably affirm, without appear- 

 ing too radical, that it is a colloidal process. This, however, means 

 but little since this is true for all of the phenomena of life. Beyond 

 this statement all we can definitely say is that the first phase of bac- 

 teriophagy consists in the approach of the bacteriophage corpuscle 

 to the bacterium, and that this is followed by its fixation to the bac- 

 terial cell. 



Unquestionably, the actual fixation is elective, as all available ex- 

 perimental data indicate. But with regard to the process which leads 

 to the contact between the bacteriophage corpuscle and the bacterium 

 there is the question as to whether it is a passive phenomenon or 

 whether it is a true chemotaxis. 



It might be assumed that the corpuscles, in violent motion because 

 of the brownian motion which animates them, become fixed only 

 when they come into contact with a susceptible bacterium. With 

 these the fixation is then elective, but it takes place only after contact 

 is effected. In this connection Kabelik^^* has recently published some 

 experiments which enforce the conclusion that a real chemotaxis 

 exists between bacteriophage corpuscles and susceptible bacteria. 



The statements of Kabelik, embodying his results, are here inserted. 



Bacterial migration may readily be studied in glass U-tubes which contain the 

 nutritive fluid and in which the bottom of the tube is filled with sterile sand. 

 For our tests these simple U-tubes are not quite adequate, and we have therefore 

 devised an apparatus which is, in effect, a combination of several of these tubes. 

 A horizontal tube, 9 mm. in diameter, and 21 cm. long, is provided with seven 

 vertical arms, about 8 cm. in length, spaced about 3 cm. from each other. In the 

 bottoms of all of these vertical tubes some very fine sand, thoroughly washed and 



