Experimental Study of Growth 245 
follows a period of slower growth; and, vice versa, those that fall 
behind make it up later, if they remain in good health. A young 
guinea pig may lose one third its weight from intestinal catarrh, 
and make the loss good later. ‘It is probable that the same is 
true of man, and that the usual and even the severer illnesses of 
childhood and youth do not greatly affect the ultimate size of 
the adult.” Pagliani shows that children brought up in poverty 
and undersized will recover in the most surprising manner if 
placed under favorable circumstances. 
“Tt has been asserted by Carpenter, Spencer, and others that 
the functions of nutrition and reproduction are in principle 
opposed to one another, because reproduction makes such a de- 
mand upon the parent for material that the supply of nutrition 
and growth of the parent is lessened.” Unfortunately for this 
philosophic generalization the premises are wrong — the grow- 
ing animal is not growing at its maximum of assimilative power. 
It has been shown that young female guinea pigs grow about the 
same whether they are carrying young or not. Minot concludes 
that “gestation does not represent a tax upon the parent but a 
stimulus — it does not impede growth, but on the contrary 
favors it.” Spencer’s “dogmatic assertions’? concerning the 
opposition of growth and reproduction are open to justly severe 
criticism. 
A guinea pig reaches its full size by the end of the first year, 
when it weighs about 775 grams. A rabbit is also full-sized a 
year after birth, and weighs 25000 grams. Man may be said to 
be full grown at the end of twenty-five years, and has then an 
average weight of 63000 grams. If we add to these times the 
length of the period of gestation, and divide the weights by these 
numbers, we obtain the average rate of growth a day. 
Guinea pig . : ; : 775+ 365+ 67 days=1.82 per diem 
Rabbit : : : 2 2500+ 365+ 30 days= 6.30 per diem 
Man . é : ‘ . 63000 + 9139 + 280 days = 6.69 per diem 
The calculation shows that man is larger than the rabbit because 
he grows for a longer period; but the daily increments are nearly 
