DUCTLESS GLANDS. 341 



are distributed ultimately in the spleen-pulp, but nothing 

 definite is known of their mode of termination. "We have 

 already referred to the fact that when these nerves are gal- 

 vanized, the non-striated muscles in the substance of the 

 spleen are thrown into contraction. 



Some Points in the Chemical Constitution of the Spleen. 

 Very little has been learned with regard to the .probable 

 function of the spleen, from the numerous chemical analyses 

 that have been made of its substance. It will therefore be 

 out of place to discuss its chemical constitution very fully, 

 and we will only refer to certain principles, the existence of 

 which, in the spleen-substance, may be considered as pretty 

 well determined. In the first place, cholesterine has been 

 found to exist in the spleen constantly and in considerable 

 quantity, and the same may be said of uric acid. In addi- 

 tion, chemists have extracted from the substance of the 

 spleen, hypoxanthine, leucine, tyrosine, a peculiar crystal- 

 lizable substance called, by Scherer, lienine, crystals of 

 hsematoidine, lactic acid, acetic acid, butyric acid, inosite, 

 amyloid matter, and some indefinite fatty principles. 1 It 

 is difficult, however, to say how far some of these principles 

 are formed by the processes employed for their extraction, 

 or are due to morbid action; certainly, physiologists have 

 thus far been unable to connect them with any definite 

 views of the probable function of the spleen. 



State of our Knowledge concerning the Functions of the 

 Spleen. The spleen is almost universal in vertebrate ani- 

 mals ; it is an organ of considerable size, and is very abun- 

 dantly supplied with vessels and nerves ; it has a complex 

 structure, unlike that of any of the true glands ; its tissue 

 presents a variety of proximate principles ; but it has no ex- 

 cretory duct, and no opportunity is afforded for the study 

 of its secretion, except as it may be taken up by the current 



1 MILSE-EDWARDS, Lemons sur la physiologic, Paris, 1862, tome vii., p. 259. 



