Objects and Methods of Study. 5 



tion, drowning, or the action of irrespirable gases. In diseases 

 of the heart and lungs it is liable to occur from the obstruction of 

 the pulmonary circulation and from the depression of the respira- 

 tory nervous centres. After death the lungs are found gorged 

 with dark red — almost black — blood, which likewise distends the 

 right heart and systemic veins, and all mucous and serous 

 membranes have a dark red, congested aspect. When breathing 

 has been arrested by mechanical violence there are, first, active 

 contractions of the respiratory muscles, but no loss of conscious- 

 ness ; then as the brain becomes charged with venous blood, con- 

 sciousness and volition are lost and convulsive movements ensue, 

 lyater still there is no respiratory effort nor convulsions, but the 

 heart continues to beat for two or three minutes longer. 



In death beginning at the brain (Coma) the sensory func- 

 tions fail first, as evidenced by drowsiness, stupor, or complete in- 

 sensibility, while the movements of heart and lungs are still tem- 

 porarily continued. Pressure on the brain by a fractured bone 

 or blood clot, or in cases of violent congestion or the rapid growth 

 of tumors, usually operates in this way. It may also result from 

 the direct action of certain poisons, like opium, belladonna, or 

 chloroform, or the ptomaines or toxins of bacteria. Causes acting 

 on the brain may, however, lead to death by syncope or asphyxia 

 when the nerve centres presiding over circulation or respiration 

 are the first to feel the full effects of the pressure or poison. 



Death from old age, with a gradual failure of the natural 

 processes of nutrition and tissue-growth, and the occurrence of 

 atrophy and various degenerations of the organs is not a common 

 occurrence in domesticated animals, so that it may be dismissed 

 without further notice. 



Actual somatic death is marked by the cessation of breathing 

 and pulse, the dilated pupils and semi-closed eyelids, the coldness 

 and palor of the visible mucous membranes and skin, and the 

 clenching of the jaws with slight protrusion of the tongue. Yet 

 these symptoms may be present in syncope and it may even be 

 impossible to detect the beats of the heart, though the subject still 

 lives. Pressure of the finger on a white portion of the skin, or on 

 a mucous membrane may give a further indication. If the in- 

 dentation made by the finger is slowly effaced and if the blood 

 again slightly reddens the part the presumption is against death. 



