2l8 MICROMETRY AND BLOOD PREPARATIONS 



Neutralize the acidity with sodium hydrate. Then add i c.c. of the phenolphthalin 

 reagent, mix and finally add several drops of i to 10 dilution of peroxide of hydrogen 

 and note the formation of a decided rose-pink coloration, varying in depth according 

 to the amount of occult blood. 



To prepare the reagent dissolve i or 2 grams phenolphthalein and 25 grams KOH in 

 100 c.c. distilled water. Add 10 grams powdered zinc and heat gently until solution 

 is decolorized. Phenolphthalin is a reduction product of phenolphthalein. 



More Reliable is the Spectroscopic Test. For this we take about 3 c.c. 

 of the concentrated ether, acetic acid, alcohol faecal nitrate and add to it 

 2 c.c. of pyridin. Then add not more than 2 to 3 drops of ammonium 

 sulphide solution. (The ammonium sulphide solution should be kept 

 in an amber-colored, glass-stoppered bottle. The solution should be 

 freshly prepared every ten days.) Examine the solution, contained hi a 

 small test-tube, with the spectroscope and the two absorption bands of 

 methaemoglobin-alkaline (haemochromogen), between D and E, show 

 a positive blood test. Comparison should be made with fresh blood, 

 in which the absorption band in the yellow is nearer line D (oxy- 

 haemoglobin spectrum). 



The great trouble about the spectroscopic test is that it will only show the presence 

 of quite large amounts of blood. // is by no means a delicate test. 



ACIDOSIS AND METHODS FOR ITS DETERMINATION 



Everyone is familar with that form of respiratory disturbance 

 associated with diabetic coma, known as Kussmaul's air hunger. Here 

 we have hyperpnoea, a form of dyspnoea typically without cyanosis, 

 and the best clinical evidence of acidosis. 



Reduced alkalinity of the blood would be a better expression than acidosis because 

 even a neutral reaction of the blood would be incompatible with maintenance of life. 



Acidosis is an important consideration in alimentary tract disturb- 

 ances of infants and children, as in infantile diarrhoeas or cyclical 

 vomiting of children. It is not infrequent in the pneumonias of 

 children. In adults we must keep the possibility of the occurrence of 

 acidosis in mind in the vomiting and eclampsia of pregnancy, in sal- 

 icylate poisoning, following chloroform anaesthesia, and in chronic 

 nephritis as well as in many infectious diseases. 



Sellard's alkaline treatment for the acidosis of cholera is a measure of the utmost 

 value. 



Starvation, whether the result of gastric ulcer, gastric carcinoma or otherwise, is a 

 recognized cause of acidosis. The insistence upon one-sided diets in children is often 



