THE SPLEEN. 67 



ish, and semi-transparent, and either cluster together, or are 

 widely separated. By Malpighi, they were considered glan- 

 dular, and by Ruysch,* as convoluted vessels. Professor 

 Soemmering, from the following paragraph, seems to'jbin in 

 the opinion of the latter : " Qui nonnunquam occurrunt, acini 

 vel glomeruli, microscopii ope accuratissime explorati nihil 

 sunt, nisi vasorum fasciculi, vel teretes penicilli aut cirri vas- 

 culosi."' According to the observations of Sir Everard Home, 

 they swell considerably after an animal has finished drinking. 



The spleen, from having no excretory duct, and conse- 

 quently, from our inability to ascertain whether it secretes, 

 has its nature and uses shrouded in mystery. No single the- 

 ory concerning it has ever been generally adopted, for specu- 

 lations have multiplied in proportion to the obscurity of the 

 subject. The idea, however, on the use of this body, which to 

 me is most reasonable, is, that it acts a subsidiary part to the 

 liver. It would seem, indeed, as a general rule in regard to 

 glandular structures and such other highly vascular organs of 

 the body as have an intermittent function, that the blood which 

 is sent to them during their state of activity, should be passed 

 off through a different channel, while they are in a state of re- 

 pose. This does a double service, it prevents superfluous se- 

 cretions, and it also keeps up the vascular equilibrium of the 

 body, as there must be always in readiness a quantity of blood 

 sufficient for the supply of any secretion which may be want- 

 ed for the time. 



This proposition will derive some additional illustrations from 

 the t fcetal state. The kidneys being then inactive the capsulae 

 renales take off their blood, and thereby prevent what would 

 otherwise be a very inconvenient secretion of urine; again, the 

 lungs being also then inactive, the circulation through them is 

 proportionately reduced, and the superabundant blood is con- 

 ducted through the thymus gland. But as the full functions 

 of the lungs and of the kidneys are established upon birth, and 

 continue uninterrupted during life, their supplementary organs, 

 the thymus gland, and the capsulae renales, are not wanted, 

 and they wither away after the early period of infantile exis- 

 tence is passed. 



In regard to the liver, its functions also suspended during the 



* Epis, Anat. IV. 



