628 THE INTERNAL SECRETIONS AND IMMUNITY. 



This feature was thought to point directly to the latter as the 

 "bactericidal agents. 



EXPLANATION OF PLATE. Fig. 1. Pfeiffer's phenomenon occurring in the 

 exudation taken from an untouched guinea-pig, the exudation having been with- 

 drawn ten minutes after the injection of 1 cubic centimeter of bouillon containing 

 one loopful of a culture of Constantinople cholera and 0.04 cubic centimeter of 

 preventive serum (of the strength of Vs milligramme). Staining with methylene- 

 blue. I, Lymphocytes. Ocular 3. Vis Zeiss. 



Fig. 2. Mass of granules placed around a collection of leucocytes. Exuda- 

 tion of a guinea-pig withdrawn nine minutes after the injection of 1 cubic centi- 

 meter of bouillon to which had been added a third of a culture of Oriental- 

 Prussia cholera and 0.04 cubic centimeter of preventive cholera serum of goat 

 (strength, 0.0002). Ocular 2. D. Zeiss. 



Fig. 3. Granular leucocyte surrounded by a zone of vibrionic granules. 

 The exudation was withdrawn twenty-five minutes after the peritoneal injection 

 of one-tenth of an agar-agar culture of Massowah vibrio. Ocular 2. Vis Zeiss. 



Fig. 4. Two mononuclear leucocytes surrounded by granules; a lym- 

 phocyte (I) and a red blood-corpuscle (h) from the same exudation. Same power. 



Fig. 5. The same cells after remaining for three and one-half hours at 26. 



Fig. 6. Five polynuclear leucocytes from the exudation withdrawn four 

 minutes after the injection into the peritoneum of a guinea-pig (highly vacci- 

 nated and prepared with 3 cubic centimeters of bouillon) of 1 cubic centimeter of 

 bouillon with one-third of an agar-agar culture of Oriental-Prussia cholera, n, 

 Nucleus of a crushed macrophage. Staining with methylene-blue. Ocular 3. 

 Vis Zeiss. 



Fig. 7. Mononuclear leucocyte filled with Courbevoie cholera vibrios. 

 Peritoneal exudation of a guinea-pig. Ocular 3. Vis Zeiss. 



Figs. 8 and 9. Two polynuclear leucocytes from the same exudation. The 

 vibrios stained gray in the plate are vibrios in the eosinophile stage. Ocular 3. 

 Vu Zeiss. 



Figs. 10 to 14. Various phases in the formation of cultures of cholera 

 vibrio (Oriental Prussia) within leucocytes. Hanging drop, stained with methy- 

 lene-blue, of the exudation of a guinea-pig hypervaccinated for almost six months 

 and prepared with 3 cubic centimeters of bouillon. The exudation was with- 

 drawn four minutes after the peritoneal injection of one-third of an agar-agar 

 cholera culture placed in 1 cubic centimeter of bouillon and kept at 38. Ocular 

 3. Vis Zeiss. 



Figs. 15 to 18. Various phases in the formation of cultures of the Kiel red 

 bacillus within leucocytes. The hanging drop was kept for twenty hours at 17 

 and was made with the exudation from an hypervaccinated guinea-pig prepared 

 with an injection of 3 cubic centimeters of bouillon. The exudation was with- 

 drawn four minutes after the introduction into the peritoneum of the Kiel 

 bacilli. Ocular 3. Vis Zeiss. 



Figs. 19 and 20. Two consecutive phases of a culture of Kiel red bacilli 

 grown from within a polynuclear leucocyte in a hanging drop of peritoneal ex- 

 udation. The drop was prepared from the exudation of an hypervaccinated 

 guinea-pig, withdrawn three hours and fifty minutes after the injection of Kiel 

 bacilli into the peritoneum, n, Nucleus. Ocular 2. Vis Zeiss. 



Then came a series of investigations upon the antitoxic 

 power of the blood and other liquids of the organism which 

 appear to us to harmonize with the views of Metchnikoff and 

 Pfeiffer. The most noteworthy were those of Hankin, von 

 Fodor, and Nuttall, whose labors led to a doctrine of which 



