From time to time during the past century reference has been made to the effects of meat diets on various animal species. The earliest papers refer to lions maintained on carcass meat in the collection of the Zoological Society of London. Crisp (1864) observed enlarged thyroids in lion cubs born at the zoo, and Bland Sutton (1888) described skeletal changes referred to as 'rickets' in cubs and young lions. Of an %week-old cub Bland Sutton wrote: 'instead of playing with its companions it preferred to remain quiet. . . ; when attempting to walk it advanced a few paces, then staggered. . . the hindquarters rolled over. . .convulsions sometimes occurred'. This cub died at 1 2 weeks: its skull was found to be softened and much thickened. Bland Sutton noticed that cubs of 6 months or more suffered a less severe form of the disease, often surviving a year or two, the only constant sign being a slow progressive paraplegia. Some cubs, to which he gave supplements of bone dust and cod-liver oil, made a good recovery, and were alive and active without any signs of paralysis 2 years later. In spite of this observation, some 25 years later Marine (1914) wrote: 'In zoological gardens where carnivores are held and bred in captivity and the diet is for the most part beef, goitre, rickets and osteomalacic states are quite common.' Baumann (1896) observed that dogs fed on flesh diets frequently had enlarged thyroids of low iodine content. Watson (1904) found that fowls fed on raw lean meat and water died, in 3-16 months, with terminal paralytic signs; their thyroids were ten times the normal weight, though histologically normal apart from occasional hyperaemia. The parathyroids were also enlarged, but of normal structure. Watson (1906) reported marked thyroid hyperplasia in suckling rats whose mothers had been fed on meat, compared with the normal thyroids of those whose mothers received a mixed diet.Heitzmann (1873) noticed that rickets developed in cats fed on milk, boiled meat, white bread, boiled potatoes and fat. He was interested in lactic acid as a factor in the aetiology of rickets, but the diet he used was certainly deficient in calcium and probably also in vitamin D. The cats showed swelling and distortion of the long-bone epiphyses after 4-5 weeks on the diet; rickets was confirmed microscopically. After 4-5 months the long bones were soft ' . . .elastic, like a fish', and at post-mortem the
The female cat possesses a characteristic and highly stereotyped pattern of sexual behaviour, which is remarkably constant in individual animals (Stricht, 1911; Greulich, 1934;Bard, 1939;Dawson, 1950;Michael, 1958). The pattern of oestrous behaviour depends upon the secretory activity of the ovaries and is never observed in immature, anoestrous or ovariectomized animals (Bard, 1939;Michael, 1961). It can therefore be regarded as a pattern of behaviour that is hormone-dependent. This study deals mainly with the activation of oestrous behaviour in ovariectomized cats stimulated by treatment with oestrogens, with particular reference to the time taken for mating to occur and the relations between the vaginal and behavioural changes.In order to interpret the results of experiments in which oestrogens were introduced directly into the substance of the brain (Harris & Michael, 1964), it was necessary first to know the effects upon both behaviour and genital tract when oestrogens were administered systemically. In the mouse (Brouha & Simonnet, 1927;Marrian & Parkes, 1930;Mirskaia & Crew, 1930; Wiesner & Mirsakia, 1930), the rat (Allen, Francis, Robertson, Colgate, Johnston, Doisy, Kountz & Gibson, 1924), the guinea-pig (Boling, Young & Dempsey, 1938), and the ewe (Cole & Miller, 1935;Robinson, 1955) it has been found that the dosage of oestrogen required to induce cornification of the vagina is less than that required to evoke mating behaviour, and hence it was important to determine whether this relation also holds true in the feline species. Further, observations upon the natural oestrous cycles of normal cats (Michael, 1961) suggested that the total pattern of sexual behaviour was organized from simpler component reflexes upon a hierarchical basis by increasing levels of ovarian hormone. In the present study oestrogens have been administered to ovariectomized cats under conditions which permit this hypothesis to be tested. The preliminary results obtained were briefly reported by Michael & Scott (1957).
June, 1958, a highly significant negative correlation between the mean frecal production (for 12 days before slaughter) and mean internal fat weight of the four differently wintered groups (each of 2 cattle ) grazing on spring pasture. The mean weight in lb. of hot carcass at slaughter in June, internal fat and daily production of frecal dry matter for the four groups over-wintered on treatments high yard, high pasture,
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