Marsupials give such a high relative incidence that especial search of their records was made, without, however, very definite result. In three of the seven cases an acute general infection existed, in one an acute peritonitis which seemed to emanate from a small ulcer in the ileum, in one an injury to the anal region was found while in the remaining two the notes would suggest that the lower intestine was atonic, judging by its distention, translucency and pallor. In five the stoppage took place in the large bowel alone, in the others both divisions being affected. It is often difficult to establish a diagnosis of constipation in birds because many varieties form a long rather dry mass in the lower small intestine, to be moistened in the cloaca for discharge. Still again the groups with capacious ceca are apt to have them filled normally with firm casts. Diagnoses of fecal inspissation and stoppage in the smaller tube have been made seldom, but one must consider also the obstruction offered by excessive urate collections either in the cloaca or lower ileum which will amount to a constipation if the cloaca be over-dilated and dried urates mixed with dirt or feathers cover the anal opening. The causes of this condition in birds are usually mechanical, inflammation being found in a small minority of cases. In the small passerine birds, seeds, sand, or parasites form the commonest findings. This is also true of parrots, while excessive urate collections are noted for both these groups. The gallinaceous birds present two reasons for fecal stoppage—disease of the ceca (see pages 205–6) and cloacitis probably secondary to anal closure by excessive urate collection. Uratic stones, varying from one to five millimetres in diameter, have been found in the cloaca in several orders. In only one case, a pheasant, did they cause ulceration and cloacitis. Sand, rust, grains and the like are found frequently, and sometimes in groups of birds, indicating that the specimens had not been put upon the correct flooring or caging. Unbroken seeds may obstruct the lumen. MECHANICAL OBSTRUCTION. Although the following is not constipation it is well to cite at this place an experience which amounted to mechanical intestinal obstruction. A number of finches were subjected to postmortem and found to have whole white millet seeds in their intestines, this being the only discoverable cause of death. Investigation revealed that during the night mice ate the canary seed in the pans, leaving only the millet, which the hungry birds consumed whole. Small birds can take a few millet and crack them when eating leisurely, but apparently not when hungry. When the food was removed at night the trouble ceased. Obstruction by sand is well illustrated by a peculiar form of pica, in a goose, which is worth citing, and calls to mind the sand disease of horses: Canada Goose ♂ (_Branta canadensis canadensis_).