Chap. II.] 



BLOOD. 



ii 



08 



A 



about g-oVo of an inch on the broad, and their thick- 

 ness about 12000 of an inch. But there are always 

 corpuscles present which are much smaller by about 

 one-third to one-half 

 than the others. In 

 normal blood these 

 small red corpuscles 

 are scarce ; in certain 

 abnormal conditions, 

 especially anaemia, or 

 poorness of blood, they 

 are more numerous. 



According to Gulliver, Welcker, and others, the 

 following are the average diameters of the red 

 blood corpuscles of various vertebrates : man, -g-^Vo \ 

 d g> Wo o ; cat > T oVo ; sheep, -^^ ; elephant, ^J T '> 

 horse, T(f Vo J rausk de er, T*^; pigeon, -^- Tr ; toad, 

 ToVir ; newt > m ; proteus, i^ ; pike, ^Vo ; shark > 



B **asr C 



lg. 6.- Various kinds of Bed Blood 

 Corpuscles. 



, Two human, one seen flat, the other 

 edgeways: B, a red corpuscle of the 

 camel ; c, two red corpuscles of the frog, 

 one seen from the broad, the other from 

 the narrow side. 



11. In a microscopic specimen of fresh unaltered blood 

 (Fig. 7) the red blood corpuscles form peculiar shorter 



or longer rolls, like so 

 many coins, from be- 

 coming adherent to one 

 another by their broad 

 surfaces, tinder various 

 conditions such as 

 when isolated, or when 

 blood is diluted with sa- 

 line solution or solutions 

 of other salts (sulphate of 

 sodium or magnesium) 

 the corpuscles lose 

 their smooth circular 

 outline, shrinking and 

 becoming crenate (Fig. 8, A). In a further stage of this 

 process of shrinking they lose their discoid form, and 



Fig. 7. Human Blood, fresh. 



A, Rouleaux of red corpuscles ; B, isolated 

 red corpuscle seen in profile ; c, iso- 

 lated red corpuscle seen flat ; D, white 

 corpuscles. 



