61 



into the arm in the same manner as adjusting the tubes for 

 micro-organisms. The current is next turned on, and the 

 speed increased gradually to 10,000 revolutions per minute, 

 and thus steadily maintained, for from two to three minutes. 

 The Hematocrit may next be removed and the percentage of 

 red corpuscles is read off from the scale. In health, the 

 volume of red corpuscles is about 50 per cent. One per cent, 

 by volume represents about 100,000 red blood corpuscles, 

 therefore by adding five ciphers to the percentage of volume, 

 it gives the number of red corpuscles in one cb. mm. of blood. 

 Thus in a given case, if the reading were 25, multiply that 

 number by 100,000, and the product 2,500,000 would represent 

 the number of red blood corpuscles in one cb. mm. of blood. 

 The amount of hemoglobin in each corpuscle may be approx- 

 imately determined, also, by dividing the quantity of hemo- 

 globin ascertained by Fleischl's instrument, by the number of 

 corpuscles determined by means of the Hematocrit. 



The white blood corpuscles or leucocytes will be found to- 

 occupy a second but much shorter column immediately above 

 the column of red corpuscles, and if leucocytes be present, even 

 though to a very slight degree, it is easily recognized. 



XVI 



238. Proteid reactions. Dilute 5 cc. of serum with 35 cc. 

 of water. Add a little litmus solution to color and neutralize 

 with 0.2% hydrochloric acid. Is alkali albumin present? 



239. To another portion add a little acetic acid and heat. 



240. Apply the xanthoproteic reaction. 



241. Acidify another portion strongly with acetic acid 

 and add a few drops of a solution of ferrocyanide of potassium. 



242. Apply Millon's reagent. 



243. Apply Piowtrowski's test (6) . 



244. To another portion add a little alcohol. 



245. Saturate another portion with ammonium sulphate. 

 This precipitates all of the proteids, globulin and albumin. 

 Filter. The filtrate does not respond to any of the tests for 

 proteids. 



