334 THE DUCTLESS GLANDS [CH. XXV. 



laries from the large blood spaces of the pulp. The veins soon 

 pass into the trabeculce, and ultimately unite to form the splenic 

 vein. This arrangement readily allows lymphoid and other corpuscles 

 to be swept into the blood -current. 



On the face of a section of the spleen can be seen usually readily 

 with tin naked eye, minute, scattered, rounded or oval whitish 

 spots, mostly from -J F to -^ inch (f to f mm.) in diameter. These 

 are the Malpighian corpuscles of the spleen, and are situated on the 

 sheaths of the minute splenic arteries. They are in fact outgrowths 

 of the outer coat of lymphoid tissue just referred to (see fig. 277). 

 Blood capillaries traverse the Malpighian corpuscles and form a 

 plexus in their interior. The structure of a Malpighian corpuscle of 

 the spleen is practically identical with that of a lymphoid nodule. 



The spleen has the following functions : 



(1.) The spleen, like the lymphatic glands, is engaged in the 

 formation of colourless Hood-corpuscles. For it is quite certain, 

 that the blood of the splenic vein contains an unusually large 

 proportion of white corpuscles; and in the disease termed leuco- 

 cythcemia, in which the white corpuscles of the blood are remarkably 

 increased in number, there is found a hypertrophied condition of 

 the spleen, especially of the Malpighian corpuscles. The white 

 corpuscles formed in the spleen also doubtless partly leave that 

 organ by lymphatic vessels. 



By stimulating the spleen to contract in a case of splenic 

 leucocythaemia by means of an electric current applied over it through 

 the skin, the number of leucocytes in the blood is almost immediately 

 increased. 



Eemoval of the spleen is not fatal; but after its removal 

 there is an overgrowth of the lymphatic glands to make up for 

 its absence. 



(2.) It forms coloured corpuscles, at any rate, in some animals ; in 

 these animals, cells are found in the spleen similar to those we have 

 described in red marrow, and called Jiccmatoblasts. In these animals, 

 if the spleen is removed, the red marrow hypertrophies. 



(3.) There is reason to believe that in the spleen many of the red 

 corpuscles of the blood, those probably which have discharged their 

 office and are worn out, undergo disintegration ; for in the coloured 

 portions of the spleen-pulp an abundance of such corpuscles, in various 

 stages of degeneration, are found, and in those cases of disease in 

 which the destruction of blood-corpuscles is increased (pernicious 

 anaemia), iron accumulates in the spleen as in the liver. It was 

 formerly supposed that the spleen broke down the corpuscles and 

 liberated hsemoglobin, which, passing in the blood of the splenic vein 

 to the liver, was discharged by that organ as bile-pigment. But this 

 is not the case; the disintegration does not proceed so far as to 



