326 THE BLOOD. 



alkalinity of the blood may diminish more rapidly after being shed 

 than tinder normal conditions, and this may account for the differ- 

 ent results which have been reached with other methods. But, on 

 the other hand, v. Limbeck'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. In diabetic 

 coma, owing to the presence of large amounts of oxybutyric acid, 

 the alkalinity may not only be much diminished, but the blood may 

 actually show an acid reaction. 



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. 



Dare's Method. This method is based upon the fact that the 

 characteristic spectrum of oxyhsemoglobin disappears at the point of 

 exact neutralization when the blood is titrated with a dilute solution 

 of tartaric acid. 



The examination is made with the aid of a special instrument, the 

 hcemoalkalimeter. 



