TiiE MicRoscolpit. S 



direct mode, accompanied by complicated nuclear changes, 

 or karyomitosis, may also be followed in the division of some, 

 at least, of these cellsv 



Studied as they so usually are, as elements of the blood, we 

 too often forget theii true nature, and regard them as peculiar to 

 this fluid. Originating in the vat-ioUs accumulations of adenoid 

 tissue throughout the body, the lymphatic glands, they form the 

 "lymphoid cells;" passing into, and circulating through, the 

 lymphatic vessels, they are the "lymph corpuscles;" on being 

 poured into the venous stream, they become the " white" cells 

 of the blood, the " leucocytes ;" passing beyond the limits of the 

 blood and lymph channels into various structures, they consti- 

 tute the " wandering cells " of connective and of other tissues ; 

 in the marrow, they are the " marmw cells ;" in short, we haVe 

 to deal with a widely distributed element, whose names are as 

 various as the locations in which it is encountered, but which 

 names all refer to one and the same morphological element. 



The genetic relation between the Colorless and the colored 

 cells of the bloody the white being regarded as the progenitors of 

 the red, yearly becomes more doubtful, while the estimation of 

 the colorless cells as independent elements, having but slight 

 direct relation with the red, gains ground, being more in accord 

 with the broader views taught by recent investigations. The 

 colorless cells of the blood are to be considered, not as younger 

 or immature forms of the red corpuscles, but as circulating 

 masses of reserved formative protoplasm, the direct descendants 

 or representatives of the great energetic mesoblastic tract ; these 

 particles-^" Protoblasts " [Kolliker], they may be called— play a 

 double role, removing broken down and effete matters, and re- 

 pairing destructive processes by supplying material for new tis* 

 suesv The white blood cells are the sanitary police of the 

 economy^ even mingling with the crowds that throng that great 

 highway of exchange, the bloody to take up and remove offen- 

 sive and injurious debris, to suppress the undesirable presence 

 of degenerate members of the community of cells, even to the, 

 arrest and imprisonment of obnioxous intruding microbes ; nor 

 are these faithful patrolmen content to limit their vigils to the 

 frequented thoroughfares, but they pass out into the tortuous by*^ 

 ways and narrow lanes of the tissues themselves, penetrating into 

 the remotest nooks and darkest corners of the lymphatic cleft?! 



