Consider now another experiment, also in rats (Fig. 3). Two identical
groups, twenty in each, from the above-mentioned stock were used in
it. They were housed in colonies: both in large cages of the same
dimensions. One group was fed on a diet similar to that used by the
Sikhs; the other on a diet such as is commonly used by the poorer
classes in England. The latter diet consisted of white bread, margarine,
over-sweetened tea with a little milk (of which the rats consumed
large quantities), boiled cabbage and boiled potato, tinned meat and
tinned jam of the cheaper sorts. It has many faults, of which vitamin
and mineral deficiencies are the chief. The first thing one noticed, as
this experiment progressed, was that the members of the former, and
well-fed, group lived happily together. They increased in weight and
flourished. The other group did not increase in weight; their growth
was stunted; they were badly proportioned; their coats were staring
and lacking in gloss; they were nervous and apt to bite the attendants;
they lived unhappily together and by the sixtieth day of the
experiment they began to kill and eat the weaker ones amongst them.