LEUCOCYTES, OR WHITE CORPUSCLES. 125 



organization of the necessary elements furnished by a blas- 

 tema, and not by the action of any special organ or organs. 



The quantity of leucocytes compared to the red corpuscles 

 can only be given approximately. It has been estimated by 

 counting under the microscope the red corpuscles and 

 leucocytes contained in a certain space. Moleschott 1 gives 

 the proportion as 1 : 335 ; others at from 1 : 300 to 1 : 500. 

 It has been found by Dr. E. Hirt, of Zittau, whose obser- 

 vations have been confirmed by others, that the relative 

 quantity of leucocytes is much increased during diges- 

 tion. He found in one individual a proportion of 1 : 

 1800 before breakfast; an hour after breakfast, which he 

 took at 8 o'clock, 1 : TOO ; between 11 and 1 o'clock, 1 : 1500 ; 

 after dining at 1 o'clock, 1 : 400 ; two hours after, 1 : 1475 ; 

 after supper at 8 P. M., 1 : 550 ; at 11J P. M., 1 : 1200. 8 The 

 leucocytes are much lighter than the red corpuscles, and when 

 the blood coagulates slowly, are frequently found forming a 

 layer on the surface of the clot, which is called the " buffy 

 coat." 



^Numerous observers, among whom may be mentioned 

 Donne, Kolliker, Gray, and Hirt, 3 have noticed a great in- 

 crease in the number of leucocytes in the blood coming from 

 the spleen, and have supposed that they are chiefly manufac- 

 tured in this organ. It is inconsistent* with the mode of 

 development of these corpuscles to suppose that any special 

 organ is exclusively engaged in their production; and their 

 persistence in animals after extirpation of the spleen shows 

 that they are developed in other situations. 



The function of the leucocytes is not understood. The 

 supposition that they break down and become nuclei for the 

 development of red corpuscles, which at one time obtained, 

 is a pure hypothesis, and has no basis in fact. 



1 KOLLIKER, Manual of Microscopic Anatomy, London, 1860, p. 521. 



2 MILNE-EDWARDS, Lemons yur la Physiologic et V Anatomic Comparee, tome 

 i., p. 350. 



8 Ibid., p. 353. 



