﻿STUDIES IN PLAGUE IMMUNITY. 



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Series 10. — Experiments toith rats. 



One 48-hour agar slant culture of "Pest Virulent" (from guinea pig number 

 1221, second transplant) was suspended in 5 cubic centimeters of saline solution. 

 A 5 cubic centimeter syringe needle was dipped in this suspension and thrust 

 beneath the skin near the root of the tail of each animal. Animals numbered 

 12(55, 1207, 12(58, and 1273 received intraperitoneally, just before being stuck with 

 the infected needle, either human serum from cases previously vaccinated against 

 plague, or horses' pest immune serum. 



Animal 

 No. 



Serum. 



Result. 



Autopsy and remarks. • 



1264 





Dead after 3-J 



Few pest bacilli in heart's blood. 







days. 



1565 



3 cc. human serum 



Dead after G\ 



Numerous pest bacilli in smears from spleen and 





case III. 



days. 



liver. 



1266 





Dead after 5 



Left inguinal bubo. Smears from it show nu- 







days. 



merous pest bacilli and a few cocci. 



1267 



2 cc. serum mixture 



do 



No organisms found in smears from blood, spleen, 





human cases VI 





near point of inoculation, or right axillary 





and VIII. 





gland. Cultures from the heart and spleen 

 developed a few colonies of pest bacilli. 



1268 



3 cc. human serum 



Dead after 3£ 



No bacilli found in the heart's blood. Countless 





case V. 



days. 



pest bacilli in smears made from tissues near 

 point of inoculation. Many bacilli swollen. 



1269 





do .. ... 



Very few pest bacilli in smears from heart's 









blood. Much more numerous in smears from 









the flank. 



1270 





Dead after 5 



Cover slips from spleen show numerous pest 







days. 



bacilli. 



1271 





Dead after 3-J 

 days. 



Pest septicaemia. Fair numbers of pest bacilli in 

 smears from heart's blood. 







1272 





do 



Fair numbers of pest bacilli in smears from 









heart's blood. 



1273 



2.5 cc. antipest serum. 



Dead after 11 



Pest septicaemia. Fair numbers of pest bacilli in 







days. 



smears from spleen. Inguinal buboes with 

 countless pest bacilli. 



1274 





Dead after 3 



Few pest bacilli in smears from heart's blood. 







days. 



1275 





Dead after 22 



Chronic pest. Buboes about point of inoculation 

 contained pest bacilli. Numerous organisms 







days. 









in smears from spleen. 



Series 13. — Experiments with rats. 



One 48-hour agar slant culture "Pest Virulent" (from monkey number 1282, 

 first transplant) was suspended in 5 cubic centimeters bouillon; a 5 cubic cen- 

 timeter syringe needle was dipped in this suspension and then thrust beneath 

 the skin of each animal near the root of the tail. Rats numbered 1308, 1310. 1312, 

 1314, 131(5, 1318, and 1320 received intraperitoneally, just prior to being stuck 

 with the infected needle, serum from human cases or from animals which had 

 previously been vaccinated or otherwise inoculated against plague. 



