126 



GENERAL ANALYSIS. 



474. THE BLOOD-CELLS, little sacs so small that nearly 

 three thousand of thenfare found in every drop of Blood, 

 and yet composing not more than one half of it, are one 

 of the abundant means by which the Blood is modified. 



FIG. 110. 



Fig. 110 : 1, 2, 3, a number of Blood-cells, 

 very much magnified. Their shape in va- 

 rious positions is very well shown. They 

 are prone to adhere, as at 3. 4, 5, G, 7 are 

 the same, still more highly magnified to show 

 the convex, 5, and concave surface, 7, in sec- 

 tion, that the same cell will exhibit at difler- 

 ent times. Their semi-transparent character 

 is shown at 6. 



475. THE BLOOD-CELLS AS THEY FLOAT IN THE BLOOD 

 constantly take from it substances that they yield back 

 to it in a changed and improved condition. 



476. THE BLOOD-CELLS ARE NOT SUFFICIENT, though 

 so numerous, to accomplish all the modifying required 

 for the Blood, nor could they be more numerous in it 

 without obstructing its flow. 



477. LARGE NUMBERS OF CELLS must be accumu- 

 lated, forming, with the other necessary parts of a struc- 

 ture, different organs, conveniently located. 



478. THE LYMPHATIC GLANDS are small organs, sit- 

 uated in great numbers in the course of the Lymphatic 

 tubes, and chiefly composed of cells that modify the 

 fluid that passes through them, and are also thought to 

 be the producers of the cells that float in the Blood. 



FIG. 111. 



Fig. Ill, a section of 

 , Lymphatic gland, iuto 

 ;== which the vessels, a, a, 

 'and from which the ves- 

 sels, b, b, lead. An im- 

 mense number of cells 

 line the passages through 

 the gland from a to b. 



474. What are ? Describe Fig. 110. 475. What is the effect of - ? 476. For 

 what ? 477. How treat ? 478. What are ? Describe Fig. 111. 



