56 



Scientific Proceedings (iio). 



regarded as specific exotoxins by Kraus and his co-workers, and 

 by Arima, who produced toxic effects in rabbits by the injection 

 of the washings of typhoid and dysentery cultures grown on solid 

 media. We have recently been told by Dr. Anderson also that in 

 immunizing horses with agar cultures of meningococci, he has 

 found it advisable to wash the cultures once in salt solution in 

 order to diminish the toxic effects noticed in horses when this was 

 omitted. Such observations also would be explained by a knowl- 

 edge of the substances we have described. We may state that 

 recently a horse turned over to Mrs. Parker, by Dr. Park for 

 immunizing with influenza culture filtrates, died after the nine- 

 teenth subcutaneous injection. These cultures were grown on 

 horse-blood-chocolate broth, a fact which should exclude ordinary 

 anaphylactic effects. 



We have worked with these substances for considerably over 

 a year, making many cultures in many different ways and using 

 several hundred rabbits, and have found that there are great 

 experimental difficulties which make it impossible for the present 

 to define the biological properties of these substances with the 

 accuracy which can be applied to more potent substances such 

 as the true toxins. We have no experimental evidence to show 

 that these "X" substances are produced by streptococci, or other 

 bacteria, during their growth within the animal body. The condi- 

 tion of rabbits injected with cultures at a time when general 

 septicemia^ensues some hours before death, is strikingly similar to 

 that which is produced one or two hours after injection with the 

 filtrates, and the filtrates produce a leukopenia similar to that 

 which occurs as the body is being overwhelmed by the strepto- 

 coccus infection. However, the low potency of the poisons and 

 other difficulties of working with them, makes it impossible at the 

 present time to approach this problem more closely. 



We cannot, therefore, at the present time do anything more 

 than submit the observed facts with the hope that experimental 

 difficulties may be overcome in the future. 



Such as they are, however, these "X" substances are very 

 definite and probably non-specific products which appear early 

 in cultures and with regularity, and which must be taken into con- 

 sideration in all work in which bacterial cultures or their deriva- 

 tives are injected into animals. 



