442 Dishtrbanccs of Digestion. 



continue to act and to transmit as usual the sugar and albu- 

 men to the blood and the fat to the chylous vessels. The 

 causes of impairment of absorbent power lie primarily in the 

 alterations of the intestinal epithelium, which normally acts 

 in fact by attracting the nutrient substance to it (Krehl), and in 

 the second place in the disturbances in the lymph follicles of the 

 intestine ; and, too, the passage of the intestinal contents may 

 be too rapid to favor absorption, the period of contact of the 

 nutrient material with the intestinal mucous surface being 

 curtailed. The terms looseness of the bozvels or diarrhoea are 

 applied to the accelerated passage of the chyme through 

 the intestine, apparent from the fluid or thin intestinal dis- 

 charges. The usual cause of this condition is a heightened peris- 

 taltic action of the intestinal musculature; which may prevail 

 throughout the intestinal tract or be restricted to the large intes- 

 tine, and is due to irritation of the sensory nerve filaments in 

 the mucous membrane, with transmission of the impulse to the 

 motor nerves of the intestinal muscles. According to Cohnheim 

 extensive and general movements of the intestine can be aroused, 

 starting from any level of the gastro-intestinal canal, by merely 

 moderately strong irritation. Hand in hand with the increased 

 movement hypersecretion from the mucous membrane may take 

 place, a transudation from the blood vessels, as another effect 

 of local irritation. The irritant substances are of innumerable 

 chemical types, including materials ingested from the outside of 

 the body (drastic purgatives) or decomposition products formed 

 in the bowel itself. According! to Krehl the ocganic acids and 

 gases (carbonic acid, hydrogen) are especially efficient in stim- 

 ulating intestinal movements. When the intestinal mucous 

 membrane is already inflamed and hypersemic even an ordinary 

 amount of irritation is sufficient to cause increased peristalsis, as 

 the nerves are even then subjected to pressure from the distended 

 blood vessels and transudate (Cohnheim) or are deprived of 

 their protective covering because of the defects in the mucous 

 membrane. Diarrhoeas may also be caused, however, by 

 prevention of absorption of water from the intestine, which 

 may be the case when salines are present in the gut, these sub- 

 stances having- a strong tendency to combine with water and 

 being themselves difficult of absorption (saline laxatives). Sud- 

 den changes of the blood currents and the blood gases, soaking 

 or chilling the skin, or putrid blood poisoning are also factors 



