366 PHYSIOLOGY CHAP. 



the caecal digestion of the horse, that the fluid collected from the 

 caecum of this animal exerted a marked digestive action on food- 

 stuffs (starch, proteins, oats, vegetables) either in vitro, or when 

 introduced into the cavity of the caecum through an artificial 

 anus (at the point of the caecum) by the help of which the 

 successive changes could be examined. 



Ellenberger and Hofmeister (1881) confirmed the alkalinity of 

 the caecal juice and its capacity of digesting both starch and 

 cellulose, with evolution of gas. They also found a small quantity 

 of peptone in the contents of the caecum, while none was present 

 in the colon or rectum. It is probable that part at least of this 

 peptone is formed in situ, and that the caecal juice has also the 

 power of digesting protein. 



It was, however, shown by Bergman and Hultgren (1903) that 

 the caecum was not a vital organ even in herbivora. After 

 cutting out the whole of the caecal tract from the remainder of 

 the intestine in adult rabbits, they made quantitative investiga- 

 tions of alimentary absorption, as compared with what took place 

 in normal, control animals. Although they came to no definite 

 conclusion as to the importance of the caecum in the digestion 

 and absorption of cellulose, their researches indicate that the 

 capacity for assimilating other food-stuffs was unaltered. Nothing 

 abnormal was noted in rabbits deprived of their caecum, except a 

 diminished capacity for ingesting large quantities of food, which 

 did not, however, interfere with their general health. 



Apart from the digestive processes carried on in the caecum of 

 herbivora by means almost exclusively of the juices secreted in 

 the small intestine, it is certain that the principal function of the 

 caecum (and, generally speaking, of the whole large intestine) is, 

 not only in these animals but also in carnivora and in man, to act 

 as a reservoir for the faecal masses, so that a large part of the 

 water and nutrient matters which they contain may be absorbed 

 and utilised. 



This fact was especially brought out by the work of Marcacci 

 (1888). He tied or excised the caecum in various animals (dogs, 

 rabbits, sheep, fowls), after which he observed disorders of defaeca- 

 tion with emission of liquid faeces, containing dextrose and some- 

 times a trace of peptones, when the animals were allowed as much 

 water as they pleased with their food. 



Berlatzky (1902) established a fistula of the caecum in dogs, 

 separating it from the large intestine and uniting its orifice with 

 the abdominal walls. He saw that a minimal secretion took place 

 during fasting, which increased considerably after ingestion of 

 food. The quality of the food had no influence on the amount 

 of secretion. The caecal juice was strongly alkaline, partly 

 fluid and partly slimy. It was incapable of digesting either 

 fibrin or egg- albumin, and failed to activate other enzymes 



