Vol. XXVI, pp. 205-208 December 20, 1913 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



THE RELATIVE LENGTHS OF THE LARGE AND SMALL 

 INTESTINES IN RODENTS. 



BY T. D. A. COCKERELL, LEWIS I. MILLER AND 

 MORRIS PRINTZ. 



A few years ago Mr. John Gutberlet, working under the 

 direction of one of us (Cockerell), made some interesting 

 studies of the visceral anatomy of rodents, and among other 

 things investigated the actual and relative lengths of the large 

 and small intestines in different species, and different examples 

 of the same species. The animals on which Mr. Gutberlet 

 worked were kindly furnished by Mr. E. R. Warren, and the 

 work is briefly referred to in The Mammals of Colorado, p. xx. 



This year we have taken up the work afresh, and have con- 

 siderably amplified and extended the earlier results. It has 

 long been known that the length of the intestine in mammals 

 varies greatly, and our facts therefore accord with those ob- 

 served by others; but we have not been able to get over our 

 surprise at the phenomenon. The alimentary canal is a part 

 of the animal constantly in use, and essential for existence, and 

 one would suppose that it would reach and be maintained at 

 the optimum length. In man it is probable that the intestine 

 is longer than necessary, but this is due to changes in food, 

 resulting principally from the invention of cooking. In man, 

 also, the superfluous parts of the canal cause disease and death, 

 and except for the intervention of the surgeon, should be 

 lessened through a process of selection. 



It might be supposed that the differences observed were clue 

 to age, at least in part; but whenever we have found foetuses, 

 the proportions of their intestines have agreed very closely with 

 those of the mother. We have, however, only examined 



54— Proc. Biol. Soc. Wash., Vol. XXVI. L913. (205) 



