22 STUDIES IN IMMUNITY. 



The fluid portion of the blood contains, then, more bactericidal 

 substance than an equal amount of the peritoneal exudate. Be- 

 sides this, the total volume of blood is far greater than that of the 

 peritoneal fluid and consequently contains very much more of this 

 destructive substance. Vibrios introduced directly into the circu- 

 lation and disseminated, are therefore exposed to the maximum 

 bactericidal action. If the phagocytes are not indispensable agents 

 in the destruction of the vibrio inoculated into the peritoneum 

 they must be still less important factors in the destruction of 

 organisms injected into the circulation. Phagocytosis, however, 

 under these latter conditions occurs energetically and rapidly. 



EXPERIMENT 3. (a) A guinea-pig weighing 420 grams had been 

 well vaccinated against the true cholera vibrio (a culture labelled 

 Eastern Prussia). One-third of a 24-hour agar culture of this 

 organism suspended in 0.6 per cent salt solution was injected into 

 the jugular vein. At intervals a drop of blood was taken either 

 from the paw or from the ear and spread on slides. After a quar- 

 ter of an hour the animal was killed and preparations were made 

 from the liver, spleen and heart's blood. The preparations were 

 fixed by 5 per cent carbolic acid solution instead of heat, and 

 stained by Ehrlich's method (eosin and methylene blue). 



Preparations of blood taken at 4, 5, 9 and 13 minutes after injec- 

 tion show phagocytes containing vibrios. These phagocytes are 

 particularly numerous in specimens taken very soon (4 or 5 minutes) ; 

 one can see well stained and perfectly intact vibrios within the 

 protoplasm. In the specimens taken 9 to 13 minutes after injec- 

 tions, and particularly in the smears from the liver and kidneys, 

 the phagocytes contain, in addition to the normal vibrios, incom- 

 pletely or irregularly stained organisms showing definite granules. 

 A culture from the heart's blood on agar gave a few colonies. 

 Cultures from the liver and kidney contained a great many more 

 colonies. 



(b) A well vaccinated guinea-pig of 530 grams weight (V. cholerse, 

 Eastern Prussia) was given a third of a culture into the jugular. 

 The animal was killed one half hour after injection; the number of 

 leucocytes had fallen from 16,500 to 8000. Phagocytosis is evident 

 in blood drawn 5, 8, and 12 minutes after injection. Many poly- 

 nuclears in smears from the spleen and lung. The leucocytes of the 



