In a study of the thermogenic functions of the corpus striatum I have been led into a reinvestigation of the question of the occurrence of specific neurotoxins. Certain substances bring about a marked change of body temperature when applied to the corpus striatum and do not produce this effect when applied to other parts of the brain (1). This would indicate a difference in chemical composition between the corpus striatum and the other parts. It is conceivable that the characteristic differences should depend upon the protein constituents and hence it might be possible, by suitable methods, to induce the formation of specific neurotoxins in case such substances really occur.
Delezenne (2) described a neurotoxic serum obtained from a rabbit by repeated intraperitoneal or subcutaneous injection of an emulsion of dog brain. This serum, when injected into the marginal vein of a dog's ear, proved fatal in 5 to 10 minutes in doses of 0.2 cc. per kilo of body weight.