136 BACTERIOLYSINS AND HEMOLYSINS 



2. Dilutions of immune serum + a heterologous culture. 



3. (a) Bouillon + typhoid-culture. 



(b) Bouillon + heterologous culture. 



The study of the bacteriolytic phenomena follows the inoculation. 

 For this purpose capillary pipettes to withdraw the peritoneal exudate are 

 prepared according to the directions of von Issaeff. 



A thin glass tube is heated in a Bunsen flame almost to the melting 

 point, then removed from the flame and immediately drawn out with a 

 sudden jerk. Very fine capillary pipettes can thus be made. 



The removal of the exudate is accomplished as follows: a small cut is 

 made with scissors through the skin of the guinea-pig's abdomen; the 

 capillary pipette, the large end of which is kept closed with the index 

 finger, is forced into the abdominal cavity with a single push. The 

 pressure of the finger is next relaxed and the tube slowly withdrawn. 

 In order to avoid injuring the intestines, the precautions usually advised 

 in intraperitoneal inoculations should be observed here. The author has 

 found Friedberger's method of holding the animal very serviceable (see 

 Fig. 5). The procedure is absolutely painless, moreover, the ordinarily 

 sensitive guinea-pigs withstand the operation almost without uttering a 

 sound. 



It is best to withdraw the exudate immediately after the injection and 

 then at intervals of five to ten, twenty, and thirty minutes, etc. Observa- 

 tions are made directly in hanging-drop preparations. Stained speci- 

 mens are less reliable and instructive because, according to the investiga- 

 tions of Radziewsky, the findings are dependent upon the kind of 

 coloring matter used. Bacteria which are in the process of dissolution 

 soon lose the power of being stained by methylene blue, while they retain 

 their affinity for carbol-fuchsin and aqueous solution of gentian violet. 

 Granules are demonstrated only incompletely in stained preparations. 



The prognosis for the animal quoad vitam is unfavorable, if bacterioly- 

 sis does not occur; good, if it does. Yet there are exceptions to the latter 

 rule, a subject to which reference will be made later on. Now that the 

 most important technical details of the Pfeiffer phenomenon have been 

 considered, the following protocol will more clearly illustrate the exact 

 procedure. 



Titration of a bacteriolytic serum (after Pfeiffer). 



