OF THE INTESTINAL CANAL, &c. ,}3 



mesenteric glands, is always white and has no tinge of red, and either undergoes no 

 coagulation, or does so very feebly and slowly. The same fact has been previously 

 shown by various anatomists, and similar appearances to those which are now to 

 be noticed have been remarked by Dr. Prout. Professor Tiedemann and Gmelin al- 

 ways observed that this fluid, when it is taken from the absorbents which had passed 

 out of the mesenteric glands, is redder, and coagulates more easily and more firmly than 

 the other : and that the chyle in the thoracic duct, above the entrance of the splenic 

 absorbents, and after being mixed with the reddish coagulable lymph, appears the red* 

 dest, and coagulates very rapidly. The gradual change of the chyle into blood, they 

 argue, seems, therefore, to be a consequence of its passage through the mesenteric 

 glands, and of the admixture of the reddish coagulable lymph supplied by the absor- 

 bents of the spleen. 



The properties of the spleen in the foetus, and in old age, support this view, In 

 tfce foetus the spleen is known to be very small, and no chyle is formed in the intesti- 

 nal canal in this stage of existence ; the spleen, accordingly, intended to assimilate the 

 alimentary matter derived from the intestinal canal, is of no importance. After birth, 

 when the* formation of the chyle begins, this organ shows itself full of blood, and in- 

 creases in size rapidly. In old" persons, the spleen is commonly diminished : it appeal's, 

 therefore, like the lymphatic glands, to decrease in size with age." 



In order to establish the second circumstance which supports their third conclusion, 

 professors Tiedemann and Gmelin had recourse to direct experiment, which fully prov* 

 ed its accuracy. They conclude by observing, that pathology furnishes many confirma- 

 tions of their opinion ; and they adduce the instances of scrofula, diseases of the chy^ 

 iopoietic viscera in general, intermittent fever, and abdominal dropsy* , 



Of the Mucous Coat of the Digestive Canal, and the Functions of the aancttt 



and large Intestines* 



Note Oo 



The mucoua membrane of tfie Digestive Tube has an amphorous and spongy structure, 

 more or less soft, and of 'variable thickness. The free surface of this membrane pre- 

 sents, 1st. Valyules formed of folds of this membrane, of the submucous tissue, and 

 of muscular fiures contained within these folds ; 2d, more or less evident depres- 

 siqns, which are generally infundibuliform, cellular, or alveolar ; the follicles differ but 

 little from the alveolar depressions ; they have a narrow neck, more or less lengthened, 

 and a dilated body lodged in the submucous tissue. They are formed of this membrane 

 turned back upon itself, and exteriorly surrounded by dense cellular tissue Supplied 

 with numerous capillaries. They vary greatly in number in different situations ; 3d, 

 small eminences called papillae, and villosities which are situated on the unattached sur- 

 face of the membrane. These assume various forms, but in general, those in the pylo- 

 ric extremity of the stomach and in the duodenum, being more broad than long, present 

 a laminated appearance ; those of the jejunum are long and straight, and are correctly 

 called villosities, whilst towards the end of the ileum, and the colon, they reassume the, 



* The nerves of the spleen are chiefly from the cceliac plexus, and form a reticulum. 

 around the splenic artery, accompanying this vessel in all its distributions ; a very few 

 minute nerves also come from the par vagum and inosculate with those of the cceliac 

 plexus. 



M. Defermon recently- found, in his experiments on the abdominal circulation, that 

 the spleen is susceptible of contraction under the influence of various substances which 

 act directly on the nervous system, such as strychnine, camphor, acetate of morphine, 

 &c. In dogs to which he had giren strychnine, the spleen, which is usually flat, rolled 

 itself into a spiral form when absorption commenced, and presented very energetic 

 contractions. The action of camphor was different : the spleen under its influence 

 became rugous, and its surface assumed a granulated appearance, producing a degree 

 of motion in the whole organ. 



The influence of these agents on a viscus, whose nerves are nearly exclusively be- 

 longing to the ganglial system, confirms our views respecting the extent of function, 

 v;hich we have attributed to this system. 



E 



