THE BLOOD. 47 



potash (30 per cent, to 50 per cent, of a saturated solution in 

 water). 



Real granules are often present in the corpuscles, as may be 

 proved by adding water in large quantity. They will then 

 become greatly distended, and bursting, the granules will be 

 scattered throughout the field. 



If finely ground vermilion is sprinkled in the liquid, some 

 of the white corpuscles will take up the granules, perhaps with- 

 out losing their amoeboid character ; finally, they may eject 

 them after a longer or shorter sojourn. 



According to Boettcher, the human red blood-corpuscle has a nucleus. He 

 exhibits it in the following way : Taking a saturated solution of corrosive subli- 

 mate in alcohol (96), he diffuses about fifty volumes with one of blood. The 

 corpuscles are deprived of their haematin, but at the same time are preserved. 

 The mixture is frequently agitated, but in about twenty-four hours it is allowed 

 to subside, when the superincumbent fluid is poured off and alcohol added. 

 By further agitation for another twenty-four hours the corpuscles are thoroughly 

 washed, and then settle at the bottom of the vessel. Prof. Boettcher claims 

 in this way to have found three classes of red globules. The first are homo- 

 geneous and shiny throughout ; the second are clear externally, but granular 

 within ; the third variety exhibit a nucleus and nucleolus. 



Development of the blood-corpuscles. In early foetal life 

 all the corpuscles are colorless (Klein). According to Balfour 

 and Foster, both colored and colorless corpuscles, at least in 

 the chick, are developed from solid sprouts of protoplasm, de- 

 rived from the middle germinal layer. There seems good rea- 

 son, however, to believe that the leucocytes are formed in part, 

 at least, from the lymphatic glands, and Klein thinks that 

 they are thrown off from the "germinating buds" of serous 

 membranes. Later, the red ones make their appearance, and 

 for a time are nucleated. The investigations of Neumann and 

 Bizzozero, showing that the red corpuscles in the medulla of 

 bones are also nucleated, favors the theory that bone-marrow is 

 one of the theatres for such corpuscular metamorphosis. 



According to Hayem the production of red corpuscles in the 

 blood is accomplished through the agency of hcematoblasts, 

 i.e., minute red corpuscles. In convalescence from acute fe- 

 vers, or after a considerable loss of blood, these smaller bodies 

 may be observed in the blood for a variable time, even some 

 weeks. 



