52 



Scientific Proceedings (iio). 



stances are immediate. The relatively greater susceptibility of 

 rabbits to the "X" substances as compared to that of guinea pigs 

 also excludes substances of the histamin class, since no such 

 difference has been noted in experiment with histamin. Also 

 histamin and other toxic amines when produced in cultures of 

 bacteria are usually found in cultures some days older than those 

 used by us. Chemical and pharmacological analysis of our poisons 

 has not yet been undertaken. 



III. 



In order, further, to investigate the importance of split products 

 of the medium, we attempted to produce the poisons with cultures 

 grown on solid media. When the streptococci were grown in 

 flat bottles on agar, chocolate agar, or Loeffler's medium for 

 20 or 22 hours, then washed up in salt solution, shaken for 2 

 minutes, filtered through Berkfeldt, and the filtrates injected 

 intravenously into rabbits, symptoms exactly analogous to those 

 produced by liquid culture products were observed, with the con- 

 stant and definite incubation time and the same train of symptoms. 

 In general, the solid media washing substances were less potent 

 than the broth culture filtrates, but there was great irregularity 

 and occasionally these filtrates killed acutely. 



In all cases proper controls were made in order to eliminate 

 agar-anaphylatoxin injury, a factor which was insufficiently 

 controlled in similar experiments of Kraus, Kraus and Doerr, and 

 Arima. This factor too is totally eliminated in those of our 

 experiments in which we grew the bacteria on Loeffler's medium. 



IV. 



The symptoms produced in the animals treated with strepto- 

 coccus preparations were entirely analogous, though less severe, 

 as a rule, to those observed in parallel experiments carried out 

 with the influenza bacillus in our laboratory by Mrs. Parker. In 

 consequence, with Mrs. Parker and Miss Kuttner, we undertook 

 a comparative study of the production of similar poisons with 

 streptococci, typhoid bacilli, and influenza bacilli, and did a few 

 isolated experiments with dysentery, meningococcus, pneumo- 

 coccus and staphylococcus. 



