WHITE BLOOD-CORPUSCLES. 85 



the action of dilute hydrochloric or sulphuric acid, without 

 any loss of its iron ; though these acids would dissolve an 

 oxide of iron or decompose a carbonate. 



The peculiar colour of heematin depends less on the 

 iron than on its other constituents, for, as Scherer and 

 Mulder have shown, hsematin may retain its colour after 

 all the iron is extracted from it. 



The blood-corpuscles also possess a small quantity of a 

 solid phosphuretted fat, in proportion of about 2 parts in 

 100 of dried corpuscles. By calcination of dried cruor 1-3 

 per cent, of brown alkaline ashes are obtained, and these 

 consist of carbonate of alkali with traces of phosphate, 0*3 ; 

 phosphate of lime, 0*1; lime O'2; sub-phosphate of iron, 

 o'i; peroxide of iron, 0-5; carbonic acid and loss 0*1. 



The White Corpuscles. 



The white corpuscles are much less numerous than the 

 red. On an average, in health, there may be one white 

 to 400 or 500 red corpuscles ; but in disease, the propor- 

 tion is often as high as one to ten, and sometimes even much 

 higher. 



In health, the proportion varies considerably even in 

 the course of the same day. The variations appear to 

 depend chiefly on the amount and probably also on the 

 kind of food taken ; the number of white cells being very 

 considerably increased by a meal, and diminished again on 

 fasting. 



They present greater diversities of form than the red 

 ones do ; but the gradations between the extreme forms 

 are so regular, that no sufficient reason can be found 

 for supposing that there is in healthy blood more than 

 one species of white corpuscles. In fheir most general 

 appearance, they are circular and nearly spherical, about 

 g-^Vo of an inch in diameter, (fig. 26). They have a grey- 

 ish, pearly look, appearing variously shaded or nebulous, 

 the shading being much darker in some than in others. 



