In speaking briefly of the preparation and use of antitoxic serums in my laboratory, it may be of interest to note a few points which indicated the advisability of the method I have used for treating animals to produce the desired serum.
The preliminary experiments, published in 18941 on the production of an immunity or resistance to tuberculosis by attenuated cultures, have been continued and are confirmatory of the first results, showing the production of great resistance and in some cases complete immunity. A detail of two sets of these experiments may be given as an instance of their general results.
The first effect of the injection of the attenuated germ was, in some instances, to cause a slight decrease in weight; sometimes a local swelling was noted at the point of injection, and occasionally an enlargement of the inguinal glands. This disappeared after some weeks. This local swelling is