CHANGES IN THE BLOOD. 75 



eacli abstraction of blood, whilst the fibrin often rose, some- 

 times considerably. The following examples are very conclu- 

 sive : — 



MM. Andral and Gavarret found that the fibrin production 

 was increased in tubercular disease. In the crude state of the 

 tubercles, the mean is about 4, when softening has commenced 

 it is about 4-5, and when cavities have formed it is from 5 to 

 5 -5, the red globules decreasing from the first. 



Deficiency of fibrin — hypoplasma, hypiuosis, or defective 

 coagulating power — is observed in various morbid states, in 

 disease, and in conditions bordering upon it, and is indicated by 

 imperfect coagulation of the blood when drawn. It is deficient 

 in all conditions where the blood is imperfectly arterialized ; and 

 this is in accordance with the physiological law that arterial blood 

 is more fibrinous than venous. Thus, in death from asphyxia, 

 the blood often remains semi-fluid, of a dark, tarry appearance, 

 and coagulates only after being exposed to the air and absorbing 

 oxygen. Various poisons seem to have the power of preventing 

 the coagulation of the blood. Among these are hydrocyanic 

 acid, carbonic acid, sulphuretted and carburetted hydrogen, and 

 ammonia. Andral states that if a concentrated solution of car- 

 bonate of soda be injected into a vein, the animal presents the 

 symptoms of blood disease, and that the blood is found fluid in 

 die vessels. The same result may be produced by arsenions 

 acid, digitalis, and oxalic acid. Other substances, although 

 analogous to the carbonate of soda, seem to have no effect. Thus, 

 the nitrate of potash does not always impede the coagulation 

 of the blood ; and Dr. Handfield Jones states that he has ob- 

 served that liquor potassa?, although given for several days, and 

 untn the animal's health was interfered with, did not at all 

 interfere with the coagulation of its blood ; and he infers from 

 these observations that it is not the alkalies, as such, nor 

 the neutral salts, as such, which produce the effects usually 

 ascribed to them upon the blood, but certain substances of 



