ALIMENTARY CANAL OF BIMANA. 



437 



forate the muscular coat and form, with the veins, an expanse 

 of network, fig. 336, e, in the loose 

 submucous areolar tissue: the capil- 

 laries, ib. a, penetrate the gastro-mu- 

 cous coat, their ultimate branches, of 



from T 5Vo tn to TsVo tn °f an mcn m 

 diam., ib. d, passing vertically along or 

 between the walls of the gastric tubes 

 to their outlets, where they form a fine 

 superficial network, b : from this the 



336 



Capillaries of the gastro-mucous membrane. 

 cxlvhi". 



Gastric tubule, from the middle of the Human 

 stomach ; magii. 140 diam. cxlvhi". 



veins commence, and return by the vertical canals, c, c, to the sub- 

 mucous network, e. 



The product of the tubules, called e gastric juice,' is a limpid 

 fluid of a pale straw colour, acidulated by hydrochloric acid, and 

 also by lactic acid (unless this be a secondary result of analysis): 

 its peculiar organic principle, called ' pepsin,' contains about two 

 per cent, more nitrogen than the ordinary proteine compounds. If 

 dilute hydrochloric acid be added to a solution of pepsin in cold 

 water, the liquid exercises solvent powers over organic substances, 

 especially animal ones, and a kind of artificial gastric juice is thus 

 produced. The natural gastric juice exercises a coagulative and 

 alterative as well as solvent power upon the food, and ' digests ' 

 or converts it into chyme. 



The canal which receives the chyme, called e small intestine,' 

 extends from the pylorus, fig. 332, p, to the caecum, C C : it is 



