The Structure of Colored Blood- Corpuscles. 281 



comparatively slight in fresh blood, as proved by the following 

 experiments, made with his -^ T inch objective, which gives 

 with the micrometer eye-piece an amplification of 3,700 diame- 

 ters. When thus magnified, the human red blood disks ap- 

 peared about one inch and one eighth in diameter, so that 

 even slight differences in their size could be accurately measur- 

 ed. Among one hundred red corpuscles freshly drawn from 

 five different persons, the maximum and minimum diameters 

 'in parts of an inch, were as follows: — 



Twenty from a white male aged 30, maximum 1-3231, minimum 1-3500 



" " " " " 38, " 1-3281, « i 3 529 



" female " 44, " 1-3249, " 1-3500 



" " an African " " 50, " 1-3182, " 1-3559 



" " a white male " 8, " 1-3231, " 1-3500 



Moreover, the smallest red disks of man, as usually met with 

 in mechanically unaltered blood, whether dry or moist, are 

 according to him larger than the largest corpuscles of an ox, 

 and a fortiori of a sheep. 



More recently, 1 he measured corpuscles of individuals of 

 fourteen different nations, one hundred of each. Of the 1400 

 corpuscles measured, the average was -^ JT (.007878 mm.) the 

 maximum -^^ and the minimum ^^ of an inch ; 1158, or 83 

 per cent., measure4 between -^^ and g-J-^ °f an inch in 

 diameter, and consequently under a power of two hundred 

 would appear about the same magnitude; the total number of 

 corpuscles of minimum measure was only six, or less than one 

 half of one per cent. ; and the total number which measured 

 the maximum was ten, or less than one per cent. 



All this is very remarkable, unless he measured mainly the 

 majority, or average sized corpuscles. He made some selec- 

 tion, for he tells us, " Instead of measuring all corpuscles, de- 

 formed or otherwise, in two directions, as proposed by Dr. Wood- 

 ward, (Phila. Medical Times, vol. Yl. p. 457), I prefer to deter- 

 mine the size of unaltered, i. e. circular corpuscles only : " and 



(1) 'On the Identity of the Bed blood Corpuscles iu different Baces of Mankind." Ameri- 

 can Journal of the Medical Sciences, January, 1877, p. 112. 



