24 SECOND LECTURE. 



vertebrates, however, the lymphoid cell is smaller than the 

 colored element. 



7 j They show a molecular proto- 



© © ^^ plasma, with a granular contour. 

 s , s A few lymphoid cells harbor, in 



®[0J ^p W^j addition, fat molecules (4). If water 

 s~\> sj\ s-^f ^ e a ^ owe< ^ to act on them, the 

 t>, v_y ^ty (~ ) nucleus immediately begins to de- 

 « /2 tach itself (5). After this we have 



JSyr^'ft'SdiS anVO nuclear forms > s«ch as the cells 6, 7, 

 9 ap rhTnuc.ts^!n:\ 6 o%^: , 1 1 kewi^ and 8 possess. Other cells show a 

 £i»"^7«^fc£d£ reniform (9), or triplicate nucleus 

 substance - (10, ID. This artificial production 



may finally break up into a number of small fragments (12). 



The lymphoid cells adhere readily, they are of a somewhat 

 sticky nature. Their specific weight is less than that of the 

 red blood corpuscles. During life we meet with the already 

 described amoeboid change of form, as well as a locomotion 

 thereby induced ; this takes place most actively in diluted 

 plasma (Thoma). The cells can also be made to take up 

 small foreign particles. 



There are one, two to three colorless blood cells to 1,000 red 

 ones in man. The number increases after a plentiful meal, after 

 the loss of blood, and also under conditions which indicate a 

 more active blood formation. An interesting phenomenon is 

 presented by the spleen. The blood flowing into it shows the 

 usual small number of lymphoid cells, while in the blood of 

 the splenic vein 5,7, 12, 15, and more of them occur. In the 

 lower groups of vertebrate animals, the number of the color- 

 less cells is more considerable ; in the frog, the proportion of 

 lymphoid cells to red blood corpuscles is I : 4-10. 



The web of the frog and the tail of its larvae are adapted to 

 examinations of the circulation. The wonderful spectacle 

 (Fig. 32), shows how the colored blood corpuscles readily and 

 rapidly pass along and among each other, while the viscous 

 lymphoid cells move much less rapidly, and not unfrequently 

 adhere for a time to the inner surface of the vessel. 



