340 SECKETION. 



smaller branches. Their calibre is estimated by Sappey as 

 about twice that of the arteries. This author regards the 

 estimates, that have put the calibre of the veins at four or 

 five times that of the arteries, as much exaggerated. 1 The 

 number of veins emerging from the spleen is equal to the 

 number of arteries of supply. 



The lymphatics of the spleen are not numerous. By 

 most anatomists, two sets of vessels have been recognized, 

 the superficial and the deep; but those who have studied 

 the subject practically have found it very difficult to demon- 

 strate the superficial layer. Sappey denies the existence of 

 any but the deep vessels; 2 and Kolliker admits that the 

 superficial vessels are generally not to be found in morbid 

 spleens, and are very scanty in perfectly healthy specimens. 3 

 The deep lymphatics have been demonstrated in the capsule 

 of Malpighi, attached to the veins and emerging with them 

 at the hilum. At the hilum, according to Kolliker, the 

 deep vessels are joined by a few from the surface of the 

 spleen. The vessels, numbering five or six, then pass into 

 small lymphatic glands, and empty into the thoracic duct 

 opposite the eleventh or twelfth dorsal vertebra. It was an 

 old idea that the lymphatics were the excretory ducts of the 

 spleen. 4 This view was revived by Hewson, 6 but it is a 

 speculation which does not demand any discussion at the 

 present day. 



The nerves of the spleen are derived from the solar 

 plexus. They follow the vessels in their distribution, and 

 are enclosed with them in the capsule of Malpighi. They 



1 Op. cii., p. 329. 



2 SAPPEY, Traite tfanatomie, Paris, 1857, tome iii., p. 331. 



3 KOLLIKER, Handbuch dcr Gewebelehre, Leipzig, 1867, S. 460. 



4 In Milne-Edwards's elaborate work on physiology, now in course of publi- 

 cation, is an exhaustive bibliographical review of the early works on the anato- 

 my and physiology of the spleen. The idea that the lymphatics were its ex- 

 cretory ducts was advanced by Eller, in 1716. (MILNE-EDWARDS, Lemons sur la 

 physiologic, Paris, 1862, tome vii., p. 233, et seq.) 



6 HEWSON, Works, Sydcnham Society Publication, London, 1846, p. 271. 



