716 SPECIAL PHYSIOLOGY. 



cases of the saving of life by this operation, have been collected by 

 Beclard. In experiments on animals, it is better to defibrinate the 

 blood, so as to prevent coagulation ;' the process of whipping the 

 blood, also, to a certain extent, oxygenates the blood. It has been 

 supposed that the fibrin itself is injurious, but the better oxygenation 

 of the beaten defibrinated blood may account for its apparent supe- 

 riority. Arterial blood has been shown to have a greater restorative 

 or stimulating effect, than venous. The serum of the blood is useless 

 for the purposes of transfusion. Water has also no effect, unless it be 

 used warm ; it is useful when the blood is loaded with carbonic acid, 

 as in asphyxia, or cold and already thick or tarry, owing to loss of 

 water, as in cholera. Solutions of common salt, or of salts selected 

 so as to imitate those of the blood, yield surprising, but only tempo- 

 rary, restorative results. The blood of one Mammalian speoies may 

 be injected, with impunity, into the veins of another species ; and, 

 contrary to what was formerly supposed, blood possessing oval red 

 corpuscles, such as the blood of Birds, does not prove fatal when in- 

 jected into the veins of Mammals, in which the red corpuscles are 

 circular, provided the injected blood be arterial, and not venous, nor 

 previously agitated with carbonic acid. (Bischoff.) Blood taken from a 

 starving animal is highly injurious, if injected into the veins of an- 

 other, causing peculiar symptoms, apparently referrible to the effects 

 of decayed or decomposed animal matter. (Bernard.) Hence the ani- 

 mal, or person, subjected to transfusion-experiment, or operation, 

 should be in good health, and recently well fed; for then, not only 

 will the loss of blood be better supported, but the blood itself will be 

 newly derived from the food ; moreover, owing to the more watery 

 character of the chyle, as compared with the blood, the fibrin in the 

 latter will be diluted, and any injurious influence which this substance 

 might produce will be diminished. 



The accidental injection of air with the blood into the veins, has 

 probably been the cause of the fatal results in some transfusion ex- 

 periments. Air so injected, or introduced by wounds of the veins in 

 the neck, when it reaches the heart, is speedily fatal, either by me- 

 chanically interfering with the functions of the valves, or by chemi- 

 cally failing to excite contraction, like pure blood ; or it may induce 

 coagulation, or obstruct the pulmonary capillaries, after it has been 

 driven with the blood, in the state of froth, through the pulmonary 

 arteries. 



Vitality of the Blood. 



- The blood, as it exists in the vessels of a living animal, is not a 

 mere physical and chemical mixture of certain substances adapted to 

 the nutritive wants of the rest of the body ; but, with or without the 

 inclosing capillaries, it is an organized fluid tissue, possessing vitality 

 like the solid tissues. Its corpuscles are evolved and disintegrated 

 like the other structural elements of the body. As we shall hereafter 

 see, these bodies are originally developed simultaneously with the ear- 

 liest vessels of the embryo, and the loss to which they are subject 



