Abstract
The difficulties experienced in studying staphylococcus food poisoning when the only available subject for experimentation was the human volunteer have been in part overcome by the observation that monkeys can be fed staphylococcus filtrates in such a way as to insure a certain proportion of definite and characteristic gastrointestinal reactions. 1 Utilizing monkey feeding as a crude method of determining the presence or absence of the significant principle, some data bearing on the nature of this principle have been obtained. In all the tests here reported only animals showing actual vomiting have been set down as yielding a positive reaction; other symptoms such as pallor, diarrhea, and evident distress have been noted but not recorded as indicating an unmistakable positive result. Not all monkeys react to the active principle inducing vomiting and consequently, before using an animal for experiment we have fed it with a filtrate of known potency. Negative results were controlled by subsequent feeding with potent filtrate. The possible development of tolerance has also been controlled.
The following results have been obtained: 1. The active principle will not distill. 2. It is not readily dialyzable. 3. It is markedly unstable to N/100 NaOH. 4. It is unstable to heat in N/100 HCl solution. 5. It is not identical with the hemolytic substance present in many staphylococcus filtrates nor does it produce a skin reaction. 6. It is completely removed from acid aqueous solution by extraction with ethyl ether or chloroform as judged by our method of assay. 7. It may be extracted from alkaline solution with ethyl ether or chloroform but the deleterious effect of alkali tends to mask such removal.
Feeding with a neutral saline or aqueous solution of the ether or chloroform extracts from which all traces of the solvent had been removed by warming in vacuo caused typical vomiting in monkeys.
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