THE FLUIDS OF THE BODY 77 



sterilization at a temperature of 120 C., injected into the 

 veins of an animal, renders its blood incoagulable. 



The preparation sold by druggists under the name " pep- 

 tone," when injected into the veins of a dog, renders its blood 

 incoagulable. Commercial " peptone " is a mixture of many 

 substances. Its anticoagulation-effect is not due to the 

 peptone which it contains. It has been supposed to be due 

 to imperfectly digested albumin and gelatin (proteoses), but 

 products of bacteric fermentation (toxins and ptomaines) are 

 more probably the active bodies. Not only is the peptonized 

 blood of a dog incoagulable, but if this blood be injected into 

 the veins of a rabbit (an animal upon which the direct injec- 

 tion of peptone has no effect), it diminishes the coagula- 

 bility of the rabbit's blood. If peptonized blood be mixed 

 in a beaker with non-peptonized blood, it prevents the coagula- 

 tion of the latter. There is little doubt but that the poison, 

 whatever it may be, acts upon the leucocytes ; and there are 

 some reasons for thinking that the poison is not contained 

 in the " peptone," but is secreted by the liver of the animal 

 into which the " peptone " has been injected. 



A still more remarkable property in relation to coagula- 

 tion must be assigned to leucocytes. The blood of a dog 

 which has been rendered incoagulable by injection of peptone 

 recovers its coagulability after a time. If a further injection 

 of " peptone " be made, the animal is found to be immune. 

 Injection of " peptone " no longer renders its blood incoagu- 

 lable. In a similar manner the blood develops a power of 

 resisting the action of agents which induce its coagulation 

 whilst circulating in the vascular system. Nucleo-proteins 

 contained in extracts of lymphatic glands and other organs 

 when injected into the veins of living animals cause their 

 blood to clot, provided they are injected in sufficient quantity. 

 If they are injected in quantity less than sufficient to induce 

 coagulation, they render the animal immune to their influence. 

 A larger quantity given to an animal thus prepared fails to 

 take effect. This brings the phenomena of coagulation and 

 resistance to coagulation to the verge of chemistry. They 

 extend into the domain in which pathology reigns. Tempting 

 though it be to record other facts with regard to these pheno- 

 mena which recent investigation has brought to light, it is 



