76 PATHOLOGY. 



particular qualities. In low fevers, influenzas of a typhoid 

 character, particularly when animals so affected are stabled 

 in ill-ventilated houses, the blood becomes remarkably fluid, 

 and gravitates, even in cases that recover, to the depending 

 parts of the body. Thus we find that in the so-called purpura 

 haemorrhagica the extremities and inferior portions of the abdo- 

 men, breast, and face become the seats of extensive swellings, 

 caused by an accumulation of a preternaturally fluid blood in 

 the vessels, and even in the tissues, whilst the appearance of 

 petechise, vibices, and the occurrence of haemorrhages are due to 

 the same cause. The partial suffocation to which animals are 

 sometimes exposed when confined in buildings accidentally or 

 otherwise burnt, produce a remarkable degree of fluidity in the 

 blood. I have often witnessed this in horses and cattle which 

 had been early removed from burning buildings, — in fact, when 

 they had not been exposed to any fire, but to the effects of the 

 smoke of smouldering straw, wood, &c. At the time, the 

 symptoms of distress have not always been noticeable, and 

 little has been thought of the matter. In the course of time, 

 varying from a few hours to three days, the animals have 

 presented symptoms of great respiratory disturbance, with 

 hsemorrhage from the vessels of the lungs, the blood presenting 

 a dark olive appearance, and coagulating but very imperfectly, 

 even when exposed to the influence of the air. In such cases, it is 

 quite fair to presume that the coagulating powers of the blood have 

 been destroyed by the action of the products of combustion con- 

 tained in the smoke, and that it — the blood — gradually accumu- 

 lates in the vessels of the lungs until they have become congested, 

 even to rupture of their walls. In apoplexy of the spleen and in 

 " septicemia " the same hypinotic condition of the blood is seen, 

 and is probably the cause of the congestions and extravasations 

 which characterise those diseases. Although it may justifiably 

 be said that imperfect coagulation, as well as the abnormal 

 fluidity of the blood, depends upon the absence of fibrin, 

 modern research has proved that fibrin, as such, does not exist 

 in the blood, but is formed by the combination of two substances 

 — or two modifications of the same substance — namely, globulin^ 

 and fibrinogen; the former of wliich existing in the serum of 

 the blood, and in some tissues of the body ; whilst the latter, so 

 ^ Fibrino-plastic. — (Schmidt.) 



