FUNCTIONS OF THE DUCTLESS GLANDS. 463 



observed to be considerably smaller than usual, and the same peculiarity pre- 

 sented itself in the colorless corpuscles of the blood. 1 Hence there seems a 

 strong probability, that, whilst the plasma of the blood is being elaborated by 

 these bodies, a constant supply of new blood-corpuscles is also afforded by them. 2 

 490. The peculiar position of the Spleen, in reference to the Portal circula- 

 tion, however, seems to mark it out as having some special function of a supple- 

 mental character. Two out of the many theories of its action which have been 

 advanced deserve particular notice in connection with this point. Many expe- 

 rimenters have come to the conclusion, that, whatever may be the other purposes 

 answered by the Spleen, it serves as a diverticulum to the Portal circulation, so 

 as to relieve its vessels from undue turgescence, in virtue of the readiness with 

 which it is distended with blood; and this under a great variety of circumstances. 

 As the portal system is destitute of valves, the splenic vein has free communi- 

 cation with the whole of it; so that the Spleen will serve as a receptacle for the 

 venous blood, when the secreting action of the Liver is feeble, so that the portal 

 circulation receives a partial check. That any cause of obstruction to the hepatic 

 circulation peculiarly affects the Spleen, has been proved by experiment; for 

 after the Vena Portse has been tied, the spleen of an animal, which previously 

 weighed only 2 oz., has been found to weigh a pound and a quarter, or ten times 

 as much. Further, it is evident that turgescence of the portal system is liable 

 to occur, when the alimentary canal is distended with food ; and this from two 

 causes the pressure on the intestinal veins, and the quantity of fluid absorbed 

 by these veins. Hence it may be conceived, that the Spleen, by affording a 

 reservoir into which the superfluous blood may be directed, serves an important 

 purpose in preventing congestion of other organs. From the observations of 

 Mr. Dobson, 3 it appears that the Spleen has its maximum volume at the time 

 when the process of chymification is at an end namely, about five hours after 

 food is taken; and that it is small and contains little blood seven hours later, 

 when no food has been taken in the interval. Hence he inferred that this organ 

 is the receptacle for the increased quantity of blood which the system acquires 

 from the food, and which cannot, without danger, be admitted into the blood- 

 vessels generally; and that it regains its previous dimensions, after the volume 

 of the circulating fluid has been reduced by secretion. This view is confirmed 

 by the fact noticed by several observers that the Spleen rapidly increases in 

 bulk after the ingestion of a large quantity of fluid, which is absorbed rather by 

 the Veins than by the Lacteals. It has been further stated in support of this 

 theory, that animals from which the Spleen has been removed, are very liable 

 to die of apoplexy, if they take a large quantity of food at a time; but that, if 

 they eat moderately and frequently, they do not suffer in this manner. Now 

 this doctrine derives its chief support from experiments on Ruminating and other 

 Herbivorous animals, whose food is very bulky, and who ingest a large quantity 

 of it at a time ; and it is in them that the organ is most distensible, and that 

 the splenic vein is best adapted, by the peculiar disposition of its coats, for the 

 reception of a very large amount of blood. The cellated structure which forms 

 a large part of the spleen in these tribes, is almost wanting in Man ; and the 

 fibrous envelop of his spleen, with its trabecular partitions, has very little either 

 of elasticity or contractility. Nevertheless, there is evidence that an extraordi- 

 nary accumulation of blood may take place in this organ even in him, from any 



1 This fact is the more weighty, as, in another case observed by Prof. Bennett, the color- 

 less corpuscles of the blood were of two distinct sizes, the smaller corresponding with the 

 nuclei of the larger ones ; and the lymphatic glands were found to be crowded with corpus- 

 cles also of two distinct sizes, exactly corresponding with those of the blood. (See "Edinb. 

 Monthly Journal," October, 1851.) 



2 This view has been ably supported by Prof. J. H. Bennett, in "Edinb. Monthly Journ.," 

 March, 1852. 



3 " London Med. and Phys. Journ.," Oct., 1820. 



