114 THE BLOOD AND ITS CIRCULATION. 



tinct, and sometimes divides the nucleus in several parts, or 

 makes two or three nuclei appear at once in one globule 



(Fig. 31, B,/,A,,&). Their pur- 



pose probably is to form the red 

 globules, and we find, between 

 these two kinds of globules some 

 intermediate elements in respect 

 to color and form. Under cer- 

 tain circumstances, and particu- 

 larly in diseases of the liver, of 

 the spleen, and of the lymphatic glands, these white globules 

 increase in number until they form one-third or one-half of 

 the globular portion of the blood, which then appears of a 

 lighter color (whence the name oi'leucemie or leucocythemia). 

 This accumulation of white globules appears to arise from 

 some obstacle to their transformation into the red globules, 

 or from their being produced in greater numbers by the 

 spleen (splenetic leucocythemia), or by the lymphatic glands 

 (lymphatic leucocythemia). But even in the physiological 

 condition we find considerable variation in the numerical 

 proportion of the white globules to the re a d : thus the former 

 diminish under the influence of abstinence, and in the case 

 of persons advanced in years ; on the other hand, they in- 

 crease after eating, after hemorrhage, in children, and in 

 women during pregnancy ; this increase, especially that after 

 eating, constitutes what is called physiological leucocytosis. 

 The white globules are, finally, more abundant in certain 

 parts of the vascular system, such as the veins of the liver 

 and of the spleen ; and this is an important fact in the study 

 of the physiology of these organs. 



b. The red globules (hematies, Gruithuisen, Robin), form the 

 principal part of the cruor (three hundred red to one white). 

 It has been calculated that a litre of blood contains five bil- 

 lions of these, which makes their entire number twenty-five 

 billions. The red globule is thus the most largely diffused 

 of the elements of the system ; and, since nearly half the 

 blood is composed of it, it forms the principal organ of the 

 whole body. The process most commonly employed to 

 determine the number of globules in any given quantity of 

 blood is that invented by Vierordt, and improved by Potain, 



* A, Fresh white globules, a, White globule in its natural fluid, b, White 

 globule in water. B, yVhite globules treated by acetic acid, a, c, .Non-nucleated 

 white globule, b, Division of the nucleus, rf, Division (more advanced) of the 

 nucleus ; /, h, i, k t still more advanced. (Virchow, " Pathologic Cellulaire.") 



