. The physiology of reproduction. Reproduction. PHASES IN THE LIFE OF THE INDIVIDUAL 665 over one per cent, to their weight; when ninety days old, less than one per cent., and still less as they grow older, until when about a year old they attain their full size. The curves in the accompanying diagrams show the daily percentage increments in weight in male and female guinea-pigs respectively, as ascer- tained by Minot. It is seen that the curve for the females is very similar to that for the males. Both show an early period of rapid decline in which the rate of growth is quickly diminish- ing,
. The physiology of reproduction. Reproduction. PHASES IN THE LIFE OF THE INDIVIDUAL 665 over one per cent, to their weight; when ninety days old, less than one per cent., and still less as they grow older, until when about a year old they attain their full size. The curves in the accompanying diagrams show the daily percentage increments in weight in male and female guinea-pigs respectively, as ascer- tained by Minot. It is seen that the curve for the females is very similar to that for the males. Both show an early period of rapid decline in which the rate of growth is quickly diminish- ing, followed by a period of slight decline in which the curve is still falling, but very much more gradually. (Figs. 142 and 143.). Pi^U£/7iicL^ S'myiMTUL'yi^, J^eon'O^ ZSen 17 U 23 3530 45 nadaifa Fig. 143.—(From Minot's Problem of Age, Growth, and Death, G. S. Putnam & Sons, and John Murray.) Minot has also investigated the rate of growth in the rabbit and in the chicken. The young rabbit, as is well known, is born in a very immature state of development after a relatively short gestation period. Correlated with this fact, it was found that the male rabbit four days after birth is capable of adding over seventeen per cent, to its weight in a single day. From that time the percentage increment drops very rapidly, so that at an age of twenty-three days the rabbit can only add a little over six per cent. After about the fifty-fifth day the decline in the growth rate, which has hitherto been rapid, becomes more gradual. In the case of the chicken, Minot's results were in a general way similar, but the rate of growth on the first day it could be measured was a nine per cent, addition to the weight,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Marshall, F. H. A. (Francis Hugh Adam), 1878-1949; Cramer, Wi
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectreproduction, bookyea
