_(j4 VETKRINARV PATHOLOGY. 



Thus, suspended brain function results in arrest of heart action 

 and respiration either of which results in somatic death. Coma 

 is a term used to designate a condition in which all conscious- 

 ness or recognition of environments is suspended but the con- 

 trol of vital functions is still maintained. 



Signs of death.— Tlie changes that occur in dead tissue are 

 of considerable importance especially to inspectors of carcasses 

 of animals, the flesh of which is intended for human consump- 

 tion. The most important post mortem changes in tissues are 

 as follows; post mortem staining (livores mortis) ; death stiffen- 

 ing (rigor mortis) ; and decomposition or putrefaction. 



Post Mortem Staiiiiiu/. — The blood usually undergoes changes 

 immediately after death. The disintegration of red blood cells 

 allows of the liberation of hemoglobin which is deposited more 

 or less extensively u]ion the inner lining of the blood vessels and 

 heart and also Alters through the vessels and stains the peri- 

 vascular tissues. The length of time after death that post mor- 

 tem staining becomes e\ident depends upon the cause of death. 

 In fact the purplish staining along the cutaneous vessels evident 

 in dead bodies may be evident in the living body of animals. Thus 

 liberation of hemoglobin takes place during life in the blood of 

 animals affected with septicemic diseases. 



Temperature changes. — The carcasses of all dead animals assume 

 the temperature of the environment sooner or later. The length 

 of time necessary for the bodv heat to pass out of a dead body 

 depends largelv upon the cause of death. In some diseases, 

 those in which tissue change is limited, the temperature is sub- 

 normal at the time of death and rapidlv assumes the environmen- 

 tal temperature after death. In other diseases, those in which 

 tissue changes are extensive, the temperature mav vary from 

 normal to considerably above normal at the time of death and 

 may increase for several hours after death. Temperature changes 

 may be extremely variable in a carcass. Also a remarkably low 

 subnormal temperature has been observed in many living ani- 

 mals, especially those in a comatose state and vet the animals 

 recover. The thermic variations should never be relied upon in 

 determining whether or not life is extinct, at least not within 

 48 hours after the animal is supposed to be dead. 



Rigor Mortis. — That the body of an animal becomes rigid after 

 death is common knowdedge to all observers. Rigor mortis re- 

 presents a condition of the muscle fibre in which it Ijecomes rigid 

 as if in a tonic contraction. The length of time after death that 

 rigor mortis appears and the length of time that it persists de- 

 pends upon the condition of the animal at the time of death. 



