A note on the desensitization of guinea-pigs

Abstract

During the course of certain experiments it so happened that I desired to reinject a comparatively large number of laboratory animals with bovine protein, and because of the danger of anaphylaxis I attempted to desensitize these before giving the large amounts of protein which I subsequently wished to use. It was in fact an endeavor to safely desensitize both rabbits and guinea-pigs so that large amounts of protein could be reinjected sub-cutaneously, intravenously and intrapleuraly. The results seemed worth recording both because of their practical bearing and because of one or two striking occurrences.

The number of animals which came into consideration were 72 guinea-pigs. On account of the character of the initial or sensitizing doses they should be divided into two groups, namely a set of 30 and a set of 42.

The former received the following initial injections :

1915, January 16. 2.5 C.C. subcutaneously.

January 21. 1.0 C.C. subcutaneously.

January 30. 0.5 C.C. subcutaneously.

February 2. 1.0 C.C. subcutaneously.

The set of 42 received only one initial dose of 0.5 C.C. on January 22, 1915.

The first reinjection (subcutaneous) was given on March 24, 1915, an interval of 50 days. It is perhaps advisable to explain the practical carrying out of the injections to make Chart I clear. Both sets of guinea-pigs (all of which were numerically tagged) were put in a large cage and the injections were carried out by taking the animal most convenient, without regard to its number, and transferring immediately after injection to a different cage. The dose first tried was 0.02 C.C. protein diluted to 0.5 C.C. with saline, but before the seventh animal was injected two guineapigs were showing toxic symptoms and died immediately. As on account had been paid to the order in which the animals had been treated it was only possible to ascertain the numbers of the six so treated.