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Rats were housed in standard activity cages and fed 1 h each day. One group of activity rats were fed in their activity cages, and another group of activity rats were fed in the colony home cages in which they resided before being moved to the activity wheel. The latter operation was designed to eliminate novelty stress inherent in the activity wheel environment which would suppress feeding. However, home cage feeding rats ate less than control rats, and had as many ulcers as activity rats fed in the activity wheel. Novelty stress, as defined by this study, did not contribute significantly to the development of the activity-stress ulcer.

SummaryYoung male rats fed for 1 hr/day only failed to adapt to restricted food intake and died within a 4-day period. All animals in this group developed extensive gastric ulceration and gastric hemorrhage. When the daily food intake was restricted to 2 hr, none of the animals expired and only 2 showed gastric lesions; no pathologic changes were seen in rats fed adlibitum.The authors appreciate the excellent technical assistance of Mr. Jack Tomlinson.

Ten male mice from each of 5 inbred strains were found to differ in resting eosinophil counts, in reliability of successive counts, in eosinophil change resulting from handling and the taking of blood samples, in adrenal weights, in behavior and in adrenalbehavioral relations. The pattern of responses for one strain over several variables cannot be used to predict the pattern of responses for any other strain.

Eighteen rats, 60 days old, and 18 rats, 110 days old, were housed in standard activity cages and fed 1 h each day for 21 days. Ten rats, 60 days old, and five rats, 110 days old, died before the end of the experiment. All rats that died revealed extensive lesions in glandular portions of the stomach. Control rats, housed in standard cages and also fed 1 h each day, did not die. Experimental rats that died were more active than experimental rats that survived, and ate less than survivors and normal control rats. This technique is proposed as a new animal model for studying gastrointestinal pathology.