370 Royal Society: Mr. Newport on the 



in width ; the edges sharply and clearly defined. On the 20th of 

 March, the author could distinctly trace the extremity of the lumi- 

 nous streak, which he concluded was the tail of a comet, below the 

 lower part of the constellation Orion, and reaching to the star y\ Eri- 

 dani ; while the stars I and e Eridani were distinctly seen with the 

 naked eye through the coma. From r\ Eridani, it extended 47° 30' 

 to a spot nearly equidistant from ■% Ononis and jj Leporis*. 



4. " Variation de la Declinaison et Intensite Horizontales Mag- 

 netiques observees a Milan pendant vingt-quatre heures consecu- 

 tives le 18 et 19 Janvier, et le 20 et 25 Fevrier 1843." Par C. Carlini, 

 For. Mem. R.S. 



5. A paper was also in part read, entitled " On the general and 

 minute Structure of the Spleen in Man and other Animals." By 

 William Julian Evans, M.D. Communicated by P. M. Roget, M.D., 

 Sec. R.S. 



April 6. — The following papers were read, viz. — 



1. " On the general and minute Structure of the Spleen in Man 

 and other Animals." By William Julian Evans, M.D. Communi- 

 cated by P. M. Roget, M.D., Sec. R.S. 



After adverting briefly to the discordant opinions of Malpighi, 

 Ruysch, and others regarding the structure of the spleen, the author 

 proceeds to detail the results of the investigations on this subject, in 

 which he has been for many years engaged. According to his ana- 

 lysis, the following are the component parts of this organ : — first, a 

 reticulated fibro-elastic tissue ; secondly, a pulpy parenchyma, con- 

 taining the Malpighian glands and the splenic corpuscles ; thirdly, 

 distinct cellular bodies ; fourthly, the usual apparatus of arteries, 

 veins, lymphatics and nerves ; fifthly, certain fluids ; and lastly, the 

 membranes or tunics by which it is invested. 



He describes the cells of the spleen as being formed of a lining 

 membrane, continued from that of the splenic vein, and strengthened 

 by filaments of the fibro-elastic tissue. The splenic vein communi- 

 cates with these cells, at first by round foramina, then by extensive 

 slits resembling lacerations ; and it ultimately loses itself entirely in 

 the cells. The cells themselves communicate freely with one another, 

 and also with the veins of the parenchyma ; and may therefore be 

 considered as in some measure continuations of the veins. This 

 structure constitutes a multilocular reservoir of great extensibility, 

 and possessing great elastic contractility ; properties, however, which 

 exist in a much less degree in the human spleen than in that of her- 

 bivorous animals ; in which animals the cellated structure itself is 

 much more conspicuous, and predominates over the parenchymatous 

 portion. As the splenic artery has no immediate communication 

 with the cells, these latter may be filled much more readily by in- 

 jection from the vein than from the artery. In the ordinary state 

 of the circulation, the blood, which has passed into the cells from the 

 veins, is pressed into the branches of the splenic veins by a force de- 

 rived from the elasticity of the fibro-elastic tissue which surrounds 



[* Other notices of the comet have appeared, in the present volume, 

 pp. 54, 147, 311 ; and in the preceding volume, p. 3^3.] 



