356 Ewarr-— Variation: Germinal and Environmental. 
scale of a balance, and the four in the other, the four were found to weigh a few 
grains more than the eight. In this case the four foetuses had evidently received 
the same amount of nourishment as the eight, and were, moreover, able to 
assimilate all they received. Had these twelve young been born, the eight small 
ones might, in course of time, have reached the same dimensions as the four large 
ones.* Very often in a litter of rabbits one or two of the young are small and 
soon die off, but I once succeeded in rearing a rabbit that, even when nearly six 
weeks old, was little more than half the weight of the other members of the 
litter. Eventually the environmental dwarf nearly reached the size of its half 
wild parent, and produced perfectly normal offspring. Sometimes a child is born 
little more than half the usual weight, owing to deficient nourishment (e.g. to one 
or more knots in the umbilical cord). Such a child may grow into a man above 
the average size and have perfectly normal descendants. On three occasions 
foals from mares ill and out of condition during the period of gestation proved 
extremely weak and helpless. Of the three foals two died during the first year, 
but the third, though at first a characteristic ‘‘ weed,” 1s now (as a four-year-old) 
a fairly presentable animal, and only measures two inches less than his dam. By 
way of testing the influence of the immediate surroundings during development, I 
placed a doe rabbit in a cellar with a north light through which the direct sun’s 
rays never penetrated during winter or spring—a cellar that by its unsanitary 
condition, and especially by its unsavoury smells, was extremely suggestive of a 
slum. This doe (after being mated with a half wild buck) was placed in the 
cellar on the 9th of April, and returned to her hutch on the 8th of May, the day 
before her young were due. ‘The young only arrived on the 12th May, when, as 
it happened, I saw them born. There were six in all, two were dead at birth, 
and the remaining four all died within twenty-four hours. Since this unhealthy 
litter the doe has produced thirty-eight young all perfectly normal. Of these, 
six to the same buck were born after a second sojourn in the cellar; but during 
the second stay of four weeks the cellar was in part flooded almost daily with 
sunshine, and it was, moreover, better ventilated. In the above instance, though 
plenty of good food was provided, the period of gestation was prolonged, and the 
vitality of the young enormously reduced. 
It would be a simple matter to give many instances of mammals born with 
one or more limbs wanting, or otherwise abnormal, owing often to constriction by 
the umbilical cord. Such ‘“ variations,” though congenital, are neither inherited 
nor yet are they transmitted—they are abnormal environmental variations. 
It thus appears that normal variations, during development (?.e. from the 
conjugation of the germ-cells to the time of hatching or birth), are frequently 
due to an inadequate supply of nourishment. 
* The fatal rabbits were within about five days of birth. 
