430 M. ARMAND RUFFER. 



In order to see exactly what does happen when micro- 

 organisms are inoculated into a living fluid containing no 

 cells, Metschnikoff^ introduced the spores and bacilli of 

 anthrax into the anterior chamber of the eye of living animals. 

 In this manner he proved that even in animals like frogs, 

 which are naturally immune, or animals rendered artificially 

 immune, e. g. sheep, the aqueous humour is a very good culti- 

 vating material for anthrax. The micro-organisms (even those 

 of the first vaccin) inoculated into the anterior chamber of the 

 eye of immune sheep, grow and multiply rapidly until arrested 

 by leucocytes, whilst the same micro-organisms inoculated into 

 the subcutaneous tissue of the same animal do not multiply. 

 The normal aqueous humour of immune animals, therefore, 

 contains no substances harmful to the bacillus of anthrax. 



Anthrax spores inoculated into the anterior chamber of the 

 eye of rabbits multiply abundantly, and cause the death of the 

 animal. In order to isolate the virus from cellular influences 

 it may be placed in small cylinders of elder-pith, or in a small 

 bag prepared from the intestines of frogs, or more simply 

 still, in filter-paper. The spores thus protected, when intro- 

 duced under the skin of frogs, grow into normal bacilli, whilst 

 the unprotected germs are devoured by amoeboid cells. On in- 

 troducing under the skin of frogs membranous bags containing 

 blood of guinea-pigs which had succumbed to anthrax, the 

 bacilli grew abundantly and preserved their virulence until 

 the sixth day at least; it is clear, therefore, that the living 

 fluids of frogs have no harmful influence on anthrax. Con- 

 versely, the living unprotected bacilli are eaten by the cells of 

 frogs. 



Very interesting also are the facts observed when anthrax is 

 inoculated into rats. Young white rats " succumb to anthrax 

 much more readily than adult ones, and by passing the virus 



' E. Metscbnikoff, " Sur la Maniere d'etre des Bacteries Charbonneuses 

 dans rOrganisme," 'Virchow's Archiv,' Dec, 1888 ('Annales,' Jan., 1889, 

 p. 41). 



' E. Metscbnikoff, "Etudes sur I'Immunite," 'Annales de I'lnstitut 

 Pasteur,' April, 1890, p. 199. 



