From 20 to 50 % of sexually mature female mice, grouped together in large cages but isolated from males since weaning, were found to be pseudopregnant as indicated by abeyance of oestrus, vaginal mucification, weight changes and mammary development. Such 'extra-coital' pseudopregnancies occurred independently of experimental handling in grouped females but were also observed, although much less frequently, in isolated mice subjected to daily examination.The duration of pseudopregnancy was found to be longer and much more variable than has previously been suggested.During the course of work involving the regular weighing of female mice it was observed that on several occasions untreated animals, completely isolated from male mice, showed marked weight fluctuations closely resembling the weight changes which occur during pseudopregnancy [Dewar, 1957]. Accordingly, the relation between these apparently spontaneous weight changes and the sexual state was investigated. The resulting observations and others associated with the existence of pseudopregnancy are recorded below. METHODSThe mice belonged to a closed colony of albinos maintained by random interbreeding for approx. 11 years. They were housed in cages containing up to twenty-five mice or, for experimental work, in smaller cages containing one to three animals. Except in breeding cages, the sexes were kept separate after weaning at 3-4 weeks of age.The mouse room was maintained at a temperature of 68-72°F. Mouse cake and water were supplied ad lib.The mice under observation were weighed twice daily and daily vaginal smears were taken. Comparisons were made with the behaviour of mice made pseudo¬ pregnant by mating with vasectomized males. Mammary gland development was investigated by preparing whole mounts of tissue stripped from the skin after fixa¬ tion in formol-saline, stained in iron haemalum, dehydrated and cleared in xylol. RESULTS Occurrence of' extra-coital ' pseudopregnancy Sixty virgin female mice, which had remained isolated from males from the time of weaning 4-5 months previously, were housed in groups of three and weighed daily for periods of 1-3 months. The majority, at some time, showed spontaneous weight

Summary Portable and Clinical Bench models of an automatically triggered auditory feedback masking device, the “Edinburgh Masker”, and their usage are described. The device was found to be effective in abolishing or greatly reducing stammering in 89% of 195 cases. The effectiveness of the portable device has continued in the majority of users during periods of observation of up to three years. In a follow‐up study of 67 subjects with six months or more experience of the Masker, 82 % considered it to be of “considerable” or “great” benefit and 67% stated that, as the result of using the device, their unaided speech fluency had improved. No undesirable side‐effects have been observed.

Some people keep in good health, appear to have a good appetite and yet remain very thin. This is a commonplace observation. Their friends may wonder what they do with the food they eat. Yet no physiological abnormality has been demonstrated in such people. Grafe (Grafe & Graham, 1911;Grafe, 1933) has indeed suggested that some people possess a mechanism that burns off any excess of food eaten. This luxus Konsumption mechanism might be set too high, and so might keep a person permanently thin. His experiments on both animals and patients are not generally accepted as reliable evidence for his thesis. In particular he failed to appreciate that starvation per se lowers the basal metabolic rate. Gulick (1922) in careful experiments on himself, a lean person, found that on a high caloric diet and a standard rigime, he gained weight more rapidly when his initial weight was lower than usual than from a start well above his usual weight. These observations were consistent with a luxus Konsumption mechanism, but as he did not control accurately his energy expenditure, they provide no conclusive evidence. We know of no other scientific evidence to support the hypothesis. Newburgh (1950) has shown how tenuous is the support for a luxus Konsumption and himself produced evidence that there is no metabolic control by direct, oxidation of a dietary excess of food.

The extra-uterine weight gain of pregnancy in mice was maintained after removal of the ovaries and placentae (by hysterectomy) by giving progesterone alone in apparently physiological concentrations. Cessation of treatment was followed by a fall in weight, as after parturition or pseudo-parturition; the degree of protection against the weight loss and the subsequent loss occurring after treatment were each proportional to the quantity of the hormone given. Stimulation of luteal activity by gonadotrophin after hysterectomy without spaying in pregnancy similarly prevented the loss of weight. Progesterone implants in non-pregnant mice caused a steady weight gain of a similar order to the extra-uterine weight increase of pregnancy, accompanied by anoestrus; removal of the tablets precipitated a rapid return of weight to initial levels and a return to oestrus. These and subsidiary findings support a hypothesis that the weight increase during pregnancy in the mouse is under the control of ovarian progesterone, the luteal activity being maintained by the presence of placentae in the uterus (probably by placental luteotrophin).Oestrogens, in the quantities given, were incapable of maintaining the weight after hysterectomy in pregnancy, with or without removal of the ovaries, and had no potentiating effect upon suboptimal quantities of progesterone. Oestrogens, therefore, appear neither to play any part in the weight gain of pregnancy nor to exhibit luteotrophic activity.Hysterectomy in the mouse was not observed to prolong the life of the corpora lutea of pregnancy.There is evidence that the maintenance of the increased body weight of pregnant mice [Newton, 1935; Brooksby & Newton, 1938; Dewar, 1953] is under endocrine control. It is independent of the presence of the foetuses but requires the presence of living placental tissue [Newton & Lits, 1938], but not the pituitary [Newton & Beck, 1939]. The demonstration that the adrenal glands are not concerned in the mechanism [Dewar, 1957] strengthens the possibility that the endocrine basis of the weight change is a direct placenta-ovary relationship. Several of the characteristics of pregnancy, e.g. suppression of oestrus, mucifica¬ tion of the vagina, parturition at term, depend upon the maintenance of the function of the corpora lutea by placental activity, an action which, since it is independent of the pituitary [Deanesly & Newton, 1940] probably consists of a direct hormonal influence of the placentae on the ovaries. The purpose of the present investigation was to determine whether the increased weight of pregnancy can be added to the list of characteristics attributable to luteal activity. To this end, the effects of proges¬ terone, oestrogen and gonadotrophin replacement on the body weight of pregnant mice after removal of the placentae (by hysterectomy), with or without spaying, have been studied, together with the influence of ovarian hormones on the weight of nonpregnant animals.A brief note of some of the findings has been published [Dewar, 1951].