118 ORGANISED FLUIDS. 



A person is apprehended on the suspicion of having been 

 concerned in a murder. On his clothes are observed certain 

 stains ; upon these he is questioned ; he admits that they are 

 blood stains, and states that he had been engaged in killing 

 a fowl, and that in this way his clothes had acquired the 

 marks. The stains are now submitted to microscopic ex- 

 amination ; the blood of which they are constituted is found 

 to belong to an animal of the class Mammalia, and not to that 

 of Aves ; discredit is thus thrown upon the party suspected, 

 fresh inquiries are instituted, fresh discoveries made, and the 

 end of all is the conviction of the accused of the crime 

 imputed. 



But a third question presents itself, to which it is very 

 necessary that a satisfactory reply should be made, viz., did 

 the blood, of which the stain is constituted, flow from a living 

 or dead body ? This query we will proceed to answer. 



If a vessel be opened during life, or even a few minutes 

 after death, the blood which issues from it in a fluid state 

 will quickly become solidified from the coagulation of the 

 fibrin. 



But if, on the other hand, a vessel be opened some hours 

 after death, the fluid blood which escapes will not solidify 

 because it contains no fibrin, this element of the blood having 

 already become coagulated in the vessels of the body in which 

 it still remains. 



Now this act of the solidification of the fibrin is deemed 

 by many to be a vital act, and to be the last manifestation of 

 life on the part of the blood. 



It would appear, however, that the coagulation of the blood 

 should not be regarded as a vital act, seeing that blood which 

 has been kept fluid for some time by admixture with saline 

 salts will coagulate when largely diluted with water, and 

 also, that blood which has been frozen previous to coagulation 

 will undergo the process of solidification after it has been 

 rendered fluid again by thawing.* 



* Dr. Polli has related a case in which the complete coagulation of the 

 blood did not take place until fifteen days after its abstraction. Gaz- 

 zetta Medica di Milando, 1844. 



