190 ORIENTAL PLAGUE chap. 



Thus, earth subjected to admixture with the juice and 

 particles of plague organs, and allowed to dry, retained its 

 infective power for a fortnight, but after lapse of three 

 weeks proved barren of infectivity. It is to be noted that 

 these experiments were carried out during the hottest 

 part of the year, when the drying was fairly rapid and 

 thorough. 



Experiment 9. — The blood, bubo, spleen, and liver of 

 a rat dead of acute (inoculated) plague were, on July 8, 

 finely minced and mixed with sand and earth ; these 

 materials being then put away to dry spontaneously, a 

 fair amount of ventilation being in each instance allowed. 

 In this condition the materials were kept for eight days 

 (July 16); they were then placed over sulphuric acid 

 for three days (July 19), by which time they were quite 

 dry and as hard as bricks. 



On this date, i.e. July 19, emulsions were made and 

 used for the subcutaneous injection of guinea-pigs. 



Guinea-pig No. 17 was injected with " sand-plague" 

 organs. 



Guinea-pig No. 18 was injected with "earth-plague" 

 organs. 



Guinea-pig No. 17 developed a small abscess on the 

 abdomen, but otherwise remained lively. Guinea-pig 

 No. 18 showed a gradually increasing soft tumour 

 (abscess) in the groin, which by the end of the week 

 (July 26) had reached the size of a pigeon's egg; the 

 animal, however, appeared otherwise lively. Both were 

 killed on July 27, but with negative result qua 

 B. pestis. Guinea-pigs injected with the pus of guinea- 

 pig No. 17, as also with the pus of guinea-pig No. 18, 

 remained unaffected. 



