THE BLOOD. 119 



Presuming, then, that the coagulation of the blood is not 

 an act of vitality, the inference to be deduced from the 

 presence of coagulated fibrin in blood stains, in which the 

 corpuscles may be detected, is scarcely weakened thereby, 

 since the finding of such fibrin in such a situation, and in 

 connexion with the blood corpuscles, scarcely admits of a 

 rational and probable explanation of its occurrence being 

 given apart from the idea that the blood had issued from a 

 body either living or but just dead, and in which coagulation 

 of the fibrin in the vessels had not occurred. 



The blood stains, therefore, which contain coagulated fibrin 

 in them, it is but little doubtful must have proceeded either 

 from a living individual, or from one but just dead ; while, 

 on the contrary, it is as little to be doubted, but that those 

 stains which do not contain solidified fibrin, must have 

 emanated from a body dead some hours, or from blood which 

 had already been deprived of its fibrin. 



From the disposition and form also of the blood spots, 

 some idea can be formed as to whether the blood had sprit 

 out of a living body or not. 



A few observations may now be made, first, on the length 

 of time after the formation of blood stains at which the 

 corpuscles can be detected ; and second, on the best mode of 

 proceeding in the examination of those stains. 



From observations which I have made, it would not appear 

 that it is necessary that the blood stain should be recent. I 

 am inclined to think that the period scarcely admits of 

 limitation. 



Thus in blood stains six months old, I have observed the 

 corpuscles presenting very nearly the form and appearance 

 proper to them when recently effused, and previous to their 

 becoming dried up. 



In the blood of the frog, six months after its abstraction 

 from the animal, I have observed the corpuscles both red 

 and white, and in the former, the characteristic granular 

 nuclei with so much clearness, that it would have been an 

 easy matter to have studied upon them the development of 

 blood corpuscles. 



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