Eight rats of an average weight of 65 grammes and approximately two and a half months old were led on an exclusively ox-flesh diet, four subjects of similar age and weight being used as controls. The meat-fed animals thrived, and were, with one exception, alive and in apparent health after six months of this feeding. They gained in weight more than the controls (see Chart 2). With the exception of four which became inordinarily fat, all the meat-fed subjects appeared to be in a perfect condition throughout the whole period of observation.
Chart 1. The influence of an ox-flesh diet on very young rats newly weaned. The dark line equals the average weight of the ox-flesh-fed rats. The arrows indicate deaths. The faint line equals the average weight of the control (bread-and-milk-fed) subjects.
I. The influence of a diet of horse-flesh on very young rats. Eleven animals from five litters were fed on horse-flesh, eight rats from the same litters being used as controls (bread and skimmed milk diet). Eight of the eleven meat-fed animals succumbed after a few weeks' diet ; the remaining three died within four months. The control subjects lived and thrived. The weight curve of one meat-fed subject is not included in the chart. These results, which are graphically represented in Chart 3, show that a diet of horse-flesh arrests the growth of, and is speedily fatal to, very young rats.
Fourteen young rats about two and a half months old were placed on a meat diet, eight control animals of a similar age and weight being fed on bread and skimmed milk. Six of the meat-fed subjects succumbed on the third day. On the morning of this day the rats appeared to be in their usual health. An hour after feeding one of them was lying on its side apparently unconscious. In a few minutes others were affected. They appeared to be paralysed. They felt cold to the touch, exhibited symptoms of tetany, and speedily became unconscious. Six succumbed within half an hour. Of the remainder some showed similar symptoms, although in a less degree, and they recovered when the diet was changed to bread and skimmed milk. After two days of the normal diet the remaining rats (five males and three females) were again placed on an exclusively horse-flesh diet. Under this regimen they now gained weight as shown in Chart 4. They exhibited symptoms of deranged nutrition such as accelerated and noisy respiration with tendency to "pol belly," but these symptoms were in the majority of animals recovered from. The females became pregnant and gave birth to four litters. At the end of the eighth month the animals were alive and in apparent good health, their average weight, however, being below the normal (Chart 4). The results of this observation may be summarised as follows : - 1. An exclusive horse-flesh diet was fatal to about 50 per cent, of young rats two and a half months old, death occurring within a few days, with symptoms of acute toxic poisoning. 2. In the remaining 50 per cent, the animals became accustomed to the diet and appeared to thrive on it, but their growth was permanently stunted, the maximum weight of the horse-flesh-fed being distinctly below the control bread and skimmed-milk-fed subjects. 3. The use of this diet in animals of this age appears not to affect the supervention of pregnancy.
Chart 2. The influence of an ox-flesh diet on young rats, the diet being commenced when the animals were between two and three months old. The dark line equals the average of eight ox-flesh-fed rats. The arrow indicates a death. The faint line equals the average of four Control (bread-and -milk-fed) subjects.
Chart 3. The influence of a horse-flesh diet on very young rats newly weaned. The dark lines equal the average weight of eleven horse-flesh-fed rats. The arrows indicate deaths. The faint lines equal the average weight of eight control (bread-aud-milk-fed) subjects.
Nine adult rats of an average weight of no grammes were put on an exclusively horse-flesh diet on 27th March On this diet their weight was well maintained (see Chart 5). Two succumbed in five months, the remainder being then in but by no means perfect condition, the most striking abnormality being the rough condition of the skin. In some rases the rate of respiration was increased, this symptom varying in severity from time to time. The general result of this observation shows that the exclusive horseflesh diet maintains the body-weight of adult rats in the majority of cases (seven out of nine) ; and also that the general nutrition of the flesh-fed animals was below that of the control bread and skimmed-milk-fed subjects.
Chart 4. The influence of a horse-fleshdiet on young rats, the diet being commenced when the animal- wen between two and three months old. The dark line equals the average weight of fourteen flesh-fed rats. The arrows indicate deaths. The faint line equal the average weight of eight control (bread-and-milk-fed) subjects.
I have already submitted evidence bearing on this subject. It has been shown that when an ox-flesh diet is commenced at a very early period of life pregnancy does not supervene, as in animals on a normal diet. Some further points of interest are supplied in the following record of one animal which had four litters in 1905. This animal, on a bread and skimmed milk diet, had a litter of nine on 22nd April. This litter lived and thrived. After weaning, the mother was transferred to an exclusively horse-flesh diet. Pregnancy supervened, and a second litter, also of nine, was born on 13th June. None of the second litter survived longer than two months. The horse-flesh diet was continued, and a third litter, six in Dumber, was born on 30th July. These succumbed within one month. The mother was then transferred to the normal bread and skimmed milk regimen, and while on this diet a fourth litter, eight in number, was born, all of which lived and thrived. In this and other meat-fed subjects it was observed that the mammary glands were less developed than in bread-and-milk-fed rats.