ANATOMY OF THE SPLEEN. 475 



showing that it is not necessary to have recourse to perfectly fresh specimens to discover 

 them if they exist. Kolliker notes the fact that they are often absent in the human sub- 

 ject when death has taken place from disease or after long abstinence. He believes that 

 they are nearly always to be found in perfectly healthy persons. The occasional absence 

 of these bodies constitutes another point of resemblance to the solitary glands of the 

 small intestine. 



The relations of the Malpighian bodies to the arterial branches distributed throughout 

 the spleen are peculiar. In specimens in which these corpuscles are easily made out, if a 

 thin section be made and the spleen- pulp be washed away by a stream of water, the cor- 

 puscles may be seen attached in some parts to the sides of the vessels, in others lying in 

 the notch formed by the branching of a vessel, and in others attached to an extremity of 

 an arterial twig, the vessel then breaking up into plexuses surrounding each corpuscle. 

 According to Sappey, the corpuscles are attached to arteries measuring from ^ to -^ of 

 an inch or less in diameter. When the artery is enclosed in its fibrous sheath, the cor- 

 puscles are applied to the sheath, but, in the smallest arteries, they are attached to the 

 walls of the vessels. The attachment of the Malpighian bodies to the vessels is very firm, 

 and they cannot be separated without laceration of the membranes. 



Spleen-pulp. "With regard to the constitution of the spleen-pulp, there is consider- 

 able diversity of opinion. While anatomists and physiologists are pretty generally agreed 

 concerning the structure and relations of the Malpighian bodies, some minutely describe 

 cells in the pulp, the existence of which is denied by others of equal authority. The 

 pulp, however, contains the essential elements of the spleen, and an accurate knowledge 

 of all the structures contained in it could hardly fail to throw some light on its function ; 

 but there is so little that is definitely known of either the anatomy or the physiology of 

 the spleen, that we shall refrain from discussing the views of different authors, referring 

 the reader for full information upon these points to elaborate works upon general anatomy. 



The spleen-pulp is a dark, reddish, semifluid substance, its color varying in intensity in 

 different specimens. It is so soft that it may be washed by a stream of water from a thin 

 section, and it readily decomposes, becoming then nearly fluid. It is contained in the 

 cavities bounded by the fibrous trabecula3, and it contains itself numerous microscopic 

 bands of fibres arranged in the same way. It surrounds the Malpighian bodies, contains 

 the terminal branches of the blood-vessels, and probably the nerves and lymphatics. 

 Upon microscopical examination, it presents numerous free nuclei and cells like those 

 described in the Malpighian bodies ; but the nuclei are here relatively much more abun- 

 dant. In addition are found, blood-corpuscles (white and red) some natural in form and 

 size and others more or less altered, with pigmentary granules, both free and enclosed in 

 cells. Anatomists have attached a great deal of importance to large vesicles enclosing 

 what have been supposed by some to be blood-corpuscles, and by others to be pigmentary 

 corpuscles. The state of our knowledge upon these points, however, is very unsatisfac- 

 tory. Some authorities deny the existence of the so-called blood-corpuscle-containing 

 cells. We shall abstain from a discussion of these disputed questions, which are at present 

 of a character purely anatomical. All that we can say of the spleen-pulp is, that it con- 

 tains cells, nuclei, blood-corpuscles, and pigmentary granules, with a yellowish-red fluid, 

 and that it is intersected with microscopic trabeculas of fibrous and muscular tissue and a 

 delicate net-work of blood-vessels. It is difficult to determine whether the blood-cor- 

 puscles come from vessels that have been divided in making our preparations or are really 

 free in the pulp ; or whether the free nuclei are normal or come from cells that have 

 been artificially ruptured. 



Vessels and Nerves of the Spleen. The quantity of blood which the spleen receives 

 is very large in proportion to the size of the organ. The splenic artery is the larg- 

 est branch of the coeliac axis. It is a vessel of considerable length and is remarkable 



