11 



into the pleura and also into the right pleura of a normal gray rabbit 

 weighing 2,150 grams. The normal rabbit died in about 18 hours, while 

 the aleuronat rabbit died only after 45 hours 21 hours after the death 

 of the control. 



The experiment was now varied so that the conditions were the same 

 as in Simon's experiments. 



Experiment C. A rabbit weighing 1,700 grams was injected in the 

 right pleura with 8 c. c. of aleuronat suspension and 48 hours later this 

 rabbit and a normal rabbit weighing 1,700 grams were each injected in 

 the right pleura with I c. c. of a 3O-hour streptococcus culture. In this 

 experiment the rabbit treated with aleuronat died in 24 hours, while the 

 control lived for five days. 



Experiment D. A rabbit weighing 1,500 grams was injected in the 

 right pleura with 9 c. c. of aleuronat suspension. Forty-eight hours 

 later this rabbit and a normal rabbit weighing 1,800 grams were each 

 injected in the right pleura with 1.5 c. c. of a 24-hour streptococcus cul- 

 ture. The normal rabbit died in 37 hours, while the rabbit treated with 

 aleuronat died in 45 hours eight hours after the death of the control. 



The results of the last two experiments agree fairly well with those 

 obtained by Simon, and we may now ask why they are different from 

 the results of Experiments A and B. Apparently this difference is due 

 to the fact that in Experiments C and D the inoculation was made some 

 thirty hours later than in Experiments A and B. 



That this is the correct explanation is indicated by the following ex- 

 periment : 



Experiment E. A rabbit weighing 2,300 grams was injected in the 

 right pleura with 9 c. c. of aleuronat suspension. Forty-eight hours 

 after this injection the rabbit was bled to death, and on opening the 

 pleural cavity it was found to contain no leucocytic exudate. 



Had this rabbit been inoculated in the right pleura forty-eight hours 

 after the injection of the aleuronat suspension, the inoculation would not 

 have been made into leucocytic exudate. That being the case we would 

 not expect that this rabbit could stand a larger dose of streptococcus 

 than a normal rabbit. In Simon's experiments, however, the inoculations 

 into the pleural cavity were made forty-eight hours after the injection 

 of aleuronat, and this is probably the reason w'hy he did not find these 

 rabbits more resistant than normal rabbits. Had he made his inocula- 

 tions within twenty-four hours after the injection of aleuronat his re- 

 sults would very probably have been different*. 



At the suggestion of Professor Hektoen I tested filtrates of virulent 

 streptococci to determine whether they are toxic for leucocytes, as has 



