192 ORIENTAL PLAGUE chap. 



Guinea-pig No. 24. — " Earth-plague " organs. 



Both animals were found dead on October 17 with 

 typical subacute plague. 



Experiment 13. — The materials of September 27 

 were used for experiment on guinea-pigs on October 20, 

 i.e. after twenty-three days' drying : — 



Guinea-pig No. 25. — " Sand-plague" organs. 



Guinea-pig No. 26. — " Earth-plague " organs. 



Both animals remained alive and unaffected. 



Experiment 14. — Gelatine cultures oiB.pestis, directly 

 derived from rats and mice dead of plague after feeding 

 and about fourteen weeks old, were on October 8 melted in 

 warm water, mixed with sand and with earth, and left spon- 

 taneously to dry in the laboratory in the manner described 

 in previous experiments. Nine days later (October 17) 

 these materials were used for injection of guinea-pigs : — 



Guinea-pig No. 27. — " Sand-gelatine " plague. 



Guinea-pig No. 28. — "Earth-gelatine" plague. 



Guinea-pig No. 28 was found dead on October 24 

 with typical subacute plague. 



Guinea-pig No. 27 was found dead on October 26 

 with typical subacute plague. 



Experiment 15. — The above materials were used again 

 for injection of guinea-pigs on October 26, i.e. after 

 eighteen days' drying : — 



Guinea-pig No. 29. — " Sand-gelatine " plague. 



Guinea-pig No. 30. — " Earth-gelatine " plague. 



Guinea-pig No. 29 died November 1 with typical 

 subacute plague. 



Guinea-pig No. 30 was found dead on November 2 

 with typical subacute plague. 



Experiment 16. — These materials were again used on 



