PHYSIOLOGICAL HMMATOLOGY. 275 



Observations and problems. 



(1) Determine in the cases of several normal individuals 

 whether the blood is normal when compared with 

 v. Fleischl's arbitrary scale. Let the same observer 

 make two or three consecutive tests of the blood of 

 each subject.* 



Record for each subject the average of the two or 

 three tests made by one observer. 



(2) Account, if possible, for any variations found. 



(3) Do the individuals who show a low haemoglobin 

 reading show also a low volume per cent, and con 

 versely ? If so, would one be justified in the conclu- 

 sion that the hemoglobin varies as the volume per cent of 

 the red blood corpuscles ? 



(4) Do the individuals who show a low haemoglobin, 

 reading, show also a smaller number of red blood cor- 

 puscles per unit volume, and conversely? If so, would 

 one be justified in the conclusion that the hcemoglobin 

 varies as the number of red blood corpuscles per unit vol- 

 ume? 



(5) Are there any conditions in which both of these 

 conclusions may be consistent with the results of the 

 reasoning at the end of the previous exercise, LIX? 



* If the same observer obtained aoproximately the same reading on 

 the second and third test of an individual's blood it may be taken for 

 granted that for comparison with each other this observer's readings 

 are sufficiently reliable. 



