THE ACTION OF MORPHINE ON THE DIGESTIVE

The earliest references to a constipating effect of opium are lost in the obscurity of medieval medical history while a constipating effect of morphine was recorded almost as soon as the alkaloid was isolated. The isolation was effected by Sertiirner in 1803 and in 1823 Legras used a morphine syrup to cure diarrhea which had lasted for many months. extensive The constipating investigations and effect of morphine has led to many and has produced a more abundant literature than any of the other morphine sequentia, save perhaps addiction. It is the purpose of this review to present a general resume of this literature and to indicate some possible lines of future investigation. Because of the effects the of restrictions of single doses. space it will be concerned primarily with Historical continuity and completeness will not be attempted. Tolerance and addiction phenomena will not be discussed and the so-called conditioned salivary reflex, the emetic effect, the effects of combinations of drugs and the general problem of the comparison of morphine, opium, heroin, dilaudid and related sub-stances will also be excluded. The review will take up such effects as may modify the digestive processes and lead to constipation. These can be discussed under three general headings: 1, motility effects; 2, effects on secretion; and 3, effects on absorption. A summarizing added under the heading of constipation. section will be Because the describable differences in the processes of digestion are so variable from species to species and because the data on the dog are the most satisfactory and abundant, this animal will be used as a basis of discussion, but additional information on the cat, rabbit an