GROWING UP FASTER

Hokitika Guardian, 26 July 1926, Page 4

GROWING UP FASTER

WHAT RATS CAN ACCOMPLISH. (By Science Service;. Can the ambition of children to “grow up” faster, and of all of us to he big and tall, ever he realised by a future generation? Perhaps, if human 1 icings can learn the trick that seems to have been mastered by .rats' in the laboratory of Dr Thomas B. Osborne, and Dr Lafayette B- Mendel, at the Connecticut' Agricultural Experiment Station. A breeding stock of experimental animals under their observation has “speeded up” the growing process by nearly a third during the past half-generation, the two scientists informed the National, Academy of Science at Washington on April 27tli. “In the course of the past 15 or more years we have had an opportunity to secure records of the rate of growth of several thousand rats under controllable conditions with respect to diet and environment,” they said. “The animals have been bred from laboratory stock without any introduction of new blood within the past 10 years. The stock diet during this period has presumably remained essentially the same, so that changes in the average rate of growth may perhaps he properly attributable to the effects of selective breeding in the attempt to secure vigorous animals for experimental use. A noticeable increase in the average rate of growth has, in fact, resulted. For example, the .average time required by male rats to grow from two ounces to seven ounces body weight has gradually decreased; it was approximately 04 days in 1012, 80 days in 1913, 70 days in 1919. 67 days in 1925. “From lime to time we have observed instances of exceptionally rapid growth under conditions of diet and environment seemingly the same ris those to which animals exhibiting the average rate of growth were subjected. This iu itself indicates a. possibility of largely accelerated growth that might ho secured more generally if the underlying causes could lie correctly ascertained. An outstanding illustration is

afforded by rats—stock colony—that hare grown from a body weight of two ounces to seven ounces in less than 25 days, in contrast with approximately 70 days usually required by comparable npimal.s. It need not he assumed that food itself determines the rate of growth; it merely gives the natural growth impulse fair play in a way that may not always have been recognised hitherto. The maximum size of animals growing at these accelerated

rates is m general not unduly large, although frequently it has been decidedly larger than the average.”.