268 THE BLOOD AND THE LYMPH 



The last two sorts of leukocytes together constitute rather more than 

 two-thirds of all the leukocytes, abut 70 per cent., the mast-cells being 

 only relatively few. They are the most active in their spontaneous 

 ameboid movement. From 1 to 4 per cent, of the polymorphonuclear 

 leukocytes contain- very coarse granules of some material which has a 

 strong affinity for acid stains. Because eosin is the most used acid dye, 

 these leukocytes are called eosinophiles or "lovers of eosin." About 

 68 per cent, of all leukocytes have finer granules which greedily absorb 

 mixtures of acid and alkaline stains, and they are accordingly some- 

 times, especially by pathologists, termed neutrophiles. Of all the white 

 corpuscles, from 0.5 to 1 per cent, absorb alkaline or basic stains 

 into their coarse, irregular granules; these are the basophiles or mast- 

 cells. Wolff maintains that the lymphocytes and the large mononu- 

 clears generally contain ephemeral basophilic granules, normally of 

 much smaller size than the others. As regards nuclear shape and 

 size there are many sorts of leukocytes intermediate between these 

 named kinds. This fact suggests a development from the small, round- 

 nuclear lymphocyte (fresh from the lymph node ?) to the polynuclear sort, 

 the nucleus elongating, bending, and gradually breaking apart into 

 several separate nuclei. There is excellent evidence, however, for the 

 truth of their different origins as stated above. The "salivary corpuscles" 

 and "colostrum corpuscles" are probably only the remains of emigrated 

 leukocytes which have become vacuolated and divided. 



The number of the leukocytes, like most facts concerning them, 

 varies very widely under different conditions and at various times. It 

 is commonly said that there is one leukocyte to every five hundred 

 erythrocytes on the average under ordinary conditions, which would 

 make about ten thousand (10,000) in every cubic millimeter of a man's 

 blood. During fasting the ratio lowers to about one in seven hundred; 

 after a meal it becomes about one to three-hundred-and-fif ty, and during 

 pregnancy, according to one set of accounts, it is one to two-hundred- 

 and-eighty. In the blood of the splenic vein there are many times more 

 leukocytes than in that of the splenic artery, and generally more in 

 veins than in arteries. In various conditions of disease the number of 

 the leukocytes varies very widely; for example, in leukemia there is such 

 an increase of leukocytes accompanied by a decrease of erythrocytes 

 that the ratio of the two may be as high as one to five. The same 

 tendency is seen in most acute fevers and in some inflammatory condi- 

 tions, a fact which is taken advantage of for the early diagnosis of many 

 abnormal conditions. 



The functions of the leukocytes are not yet well known. We may 

 mention several, however, which appear to be fairly certain. The most 

 important of these perhaps is that of scavenger. In this work they serve 

 as protectors of the organism's tissues from numerous poisons, organized 

 and unorganized, and are then termed phagocytes ("devouring cells"). 

 Scattered about the tissues and the circulation in such enormous numbers, 

 and with spontaneous movements, they are admirably adapted to serve 



