310 THE BLOOD. 



faulty technique, as with his method (see below) no difference could 

 be shown to exist between normal and pathological conditions. It is 

 conceivable, of course, that in disease the alkalinity of the blood 

 may diminish more rapidly after being shed than under normal con- 

 ditions, and this may account for the different results which have 

 been reached with other methods. But, on the other hand, v. Lim- 

 beck's method may likewise not be free from error. 



The tenacity with which the living organism tends to maintain 

 the normal composition of the bodily fluid is, of course, well known, 

 but that it is not always able to do so is also an established fact. 

 Herbivorous animals thus rapidly die when given large amounts of 

 mineral acids, and it may be shown that the alkalinity of their blood is 

 then markedly diminished. In cases of poisoning with strychnin, 

 arsenious acid, carbon monoxide, and amyl nitrite, moreover, where a 

 marked albuminous decomposition occurs and lactic acid appears in 

 the urine, the same result is obtained. Carnivorous animals, on the 

 other hand, are more resistant in this respect, and will stand much 

 larger amounts. The result, however, is the same. 



Lbwy's Method. Five c.c. of blood, obtained from one of the 

 superficial veins of the arm, are allowed to flow into a small flask, 

 which is provided with a long and partially graduated neck, and 

 contains 45 c.c. of a 0.25 per cent, solution of ammonium oxalate. 

 Coagulation is thus prevented, and the blood made lake-color i. e., 

 the hemoglobin is dissolved from the stroma of the red corpuscles. 

 The mixture is then titrated with a one-twenty-fifth normal solution 

 of tartaric acid, using as an indicator lacmoid paper which has been 

 soaked in a concentrated solution of magnesium sulphate. The 

 number of cubic centimeters employed to neutralize the 5 c.c. of 

 blood, multiplied by 0.0016, will then indicate the degree of alka- 

 linity in terms of sodium hydrate. The percentage is obtained by 

 multiplying the resulting figure by 20. 



v. Limbeck's Method. Ten c.c. of blood are allowed to flow 

 into 200 c.c. of boiling water, to which 5 c.c. of a one-tenth nor- 

 mal solution of hydrochloric acid have been added. The resulting 

 solution, which is clear and of a brownish color, is now retitrated 

 with a one-tenth normal solution of sodium hydrate, using as indi- 

 cator the syntonin precipitate which occurs on neutralization. The 

 difference between the 10 c.c. of the hydrochloric acid and the 

 sodium hydrate solution is multiplied by 0.004. The result indi- 

 cates the alkalinity of the 5 c.c. of blood, and to obtain the per- 

 centage this is multiplied by 20. 



The Chemical Composition of the Blood as a Whole. 



As the blood constitutes the most important channel through 

 which the food-stuffs reach the various tissues of the body, and 

 through which waste matter is carried away, we may expect to 

 find here representatives of both classes of substances. This is 



