SummaryBlood glucose and glucose tolerance tests demonstrated that many male MM mice are diabetic. Serial urine sampling showed that the diabetes occurred only in mature MM males and consisted of a single self-limiting episode. Histological examination of the pancreas, together with measurements of body weight, glycosylated haemoglobin and plasma insulin, revealed that the diabetes was of the maturityonset insulin-resistant type. Bacteriological examination of the urine samples showed that urinary tract infection, a known feature of male MM mice, occurred in the diabetics but only after the onset of hyperglucosuria.It was concluded that the high urinary glucose levels of diabetic MM males are of prime importance in the aetiology of the renal infection which occurs rarely in non-diabetic MM males or in other strains in the colony. An infectious aetiology for the diabetes per se was excluded by the existence of diabetes in germfree MM males.

SummaryGram-positive bacilli, originating from the diet, are present in the faeces of germ-free mice in this Unit. Although these organisms have never grown on culture and are assumed to be dead it was considered desirable to test this by non-cultural methods because some gut bacteria are difficult or impossible to grow in vitro by present techniques. Germ-free mice were fed a synthetic diet free from live or dead organisms for 10 days during which time the bacilli disappeared from the faeces, re-appearing when the usual diet was re-introduced. This was regarded as confirmation of the non-viability of the bacilli. The use of Wayson's stain for confirmation of non-viability was found to be inappropriate since it produced falsepositive reactions with irradiation-killed bacteria.

Inhibition of a variety of commercial test strips for hyperglucosuria was experienced in laboratory mice. All mouse strains tested were found to have sufficiently high levels of ascorbic acid to cause inhibition, and male levels were higher than those of females. A regime to obtain optimum detection of positive results is discussed.

Eczematous lesions in VM mice were invariably infected with Staphylococcus pyogenes aureus. A variety of preparations was used in treatment and although most were ineffective, one combining steroid and antibiotic therapy achieved remarkable results.