356 THE HUMAN BODY. 



muscles and passed from them to the circulating fluid is 

 essential to the general health of the Body. There are, how- 

 ever, so many muscles that the removal of some of them, as 

 when a limb is amputated, does not cut off the kreatin supply, 

 and so disease does not result. When, on the other hand, an 

 organ is unique, as the thyroid, or exists only in a single pair, 

 as the suprarenals, then removal or extensive disease, by de- 

 priving the system of the peculiar internal secretion of the 

 organ concerned or, possibly, from the accumulation within 

 the blood of substances which it is the function of the missing 

 part to absorb and destroy, may, often in fact does, lead to 

 widespread nutritional changes, resulting in death. 



The Spleen. This is an organ situated at the left end of 

 the stomach (//, Fig. J-H 1 )) and is about 110 grains (G oz. ) in 

 weight. Its size is, however, very variable; it enlarges dur- 

 ing digestion and shrinks after it until the next meal. In 

 many fevers, especially in those of malarial nature, it also 

 becomes enlarged, frequently to a very great extent, and this 

 enlargement may become permanent, constituting the so- 

 called " ague-cake." In color the spleen is dark red, but if 

 cut across numerous white spots of about 1 mm. (^ inch) 

 diameter are seen scattered over the surface of the section : it 

 is very richly supplied with blood which is carried away by 

 the splenic vein (7, Fig. 119) and poured into the portal vein. 

 The spleen possesses on its exterior a connective-tissue capsule 

 very rich in elastic fibres and giving off numerous bands 

 (trabeculcB] which branch and interlace throughout the organ 

 forming a spongy mass, in the spaces of which is contained a 

 soft red pulp of peculiar structure. The arteries of the organ 

 by frequent branching are reduced to almost capillary size, 

 and these terminal twigs enter into the pulp, and there, los- 

 ing all coats but the lining epithelium, assume the structure 

 of capillaries. The cells forming the walls of these ca- 

 pillaries next separate from one another so as to leave 

 clefts between them, and at the same time become irregu- 

 larly branched and, joining by their branches, form a sup- 

 porting framework or reticulum through the pulp, into 

 which latter the blood is poured freely through the spaces 

 between the cells. The main mass of the splenic pulp con- 

 sists of red blood-corpuscles, some normal in appearance, 

 some appearing partly broken down; mixed with these are 

 some white corpuscles, arid some larger colorless amreboid 



