BLOOD AND LYMPH. 



191 



SPECIES. 



Salamander (jSalamandra mac.'] . 



(Proteus angu.) . . 



Sturgeon (Acipenser St.} . . . 



Carp (Cyprinns Gobio) . . 



3. WHITE BLOOD-CORPUSCLES. 



The white blood-cells contain no hemoglobin and are nucleated 

 elements which, under certain conditions, possess ameboid move- 

 ment. Their size varies from 5 // to 12 //, and they are less numer- 

 ous than the red blood-corpuscles, one white blood-cell to from 

 three hundred to five hundred red cells being a normal proportion. 



Fig- 157. From the normal blood of man; X I2O (from dry preparation of H. 

 F. Miillerj : a, Red blood - cell ; b, lymphocyte; c and (/, mononuclear leucocytes; e, 

 transitional leucocyte ; f and g, leucocytes with polymorphous nuclei. 



Flemming ascribes a fibrillar structure to the protoplasm of white 

 blood-cells, and was the first to observe a centrosome situated near 

 the nucleus. M. Heidenhain made the observation that the white 

 blood-cells possessed several centrosomes grouped to constitute a 

 microcenter (microcentrum) about which the fibrillar structure of the 

 protoplasm was arranged radially. The meshes of the fibrillar net- 

 work are filled with a more fluid interfibrillar substance, in which are 

 found the specific granules to be mentioned later. In the normal 

 blood the white blood-cells vary in size and structure, and the fol- 

 lowing varieties are distinguished : (i) Small and large lymphocytes ; 

 (2) mononuclear leucocytes ; (3) transitional leucocytes ; (4) leuco- 

 cytes, either polymorphonuclear or polynuclear. 



The lymphocytes form about 20% of the white blood-cells. 



