48 BLOOD PLATELETS. [BOOK i. 



the plasma ; both are cells which eat and both therefore may be 

 spoken of as " phagocytic." But the hyaline cell appears, under 

 ordinary circumstances, to be more active in its movements and 

 more ready to ingest solid matters than the obscurely granular 

 cell. In the case of both cells, the matters ingested may be 

 changed by the action of the cell-substance, broken up, and 

 partially dissolved; they may be digested in fact. And both 

 forms may contain granules or particles the result of material so 

 ingested. 



A small cell, characterized by the scanty amount of cell- 

 substance (Fig. 1, C) surrounding the nucleus, which is spherical 

 and which exhibits a nuclear network, seems to be a young or 

 immature corpuscle, possibly a young form of the hyaline cell. 



Very scanty in the blood under normal circumstances but 

 abundant in certain parts of the lymph system is a corpuscle 

 (Fig. 1, D) of somewhat large size with an irregular or lobed 

 nucleus, and with a cell-substance the striking feature of which 

 is that it is laden with numerous coarse, obviously discrete 

 granules. These granules moreover stain very rapidly and deeply 

 with the dye eosine; hence these corpuscles have been called 'eosino- 

 phile cells/ The smaller obscure granules of the obscurely 

 granular corpuscle do not stain readily with eosine, though they do 

 stain with certain other special dyes. The eosinophile corpuscle 

 is under ordinary circumstances sluggish in its amoeboid move- 

 ments and is not known to ingest solid particles. Indeed we have 

 reason to think that the eosinophile granules are not to be regarded 

 as food particles taken in from without, but that they are the 

 result of the metabolism of the cell-substance, that they are 

 formed by the cell itself. We may probably look upon them as 

 being of the same order with the granules which we shall study 

 later on as characteristic of secreting cells. 



Lastly, a very infrequent corpuscle is one (Fig. 1, E) which 

 resembles the eosinophile corpuscle in having a lobed or irregular 

 nucleus and in having the cell substance more or less loaded with 

 discrete granules ; but the granules are small and do not stain 

 eagerly with eosine, though they do stain readily with certain basic 

 dyes, such as methyl-blue. 



What are the exact relations of these several forms, how far 

 they are to be regarded as distinct kinds or merely phases of the 

 same kind, must be left for future inquiry. 



Blood Platelets. 



33. In a drop of blood examined with care immediately 

 after removal, may be seen a number of exceedingly small bodies 

 (2 fji to 3 fji in diameter) frequently disc-shaped but sometimes of a 

 rounded or irregular form, homogeneous in appearance when quite 



