FIELDS, GRAPHS, AND OTHER DATA ON FETAL GROWTH. 59 



Out of a total of 2,298 cases as plotted for weight 252, or 10.9 per cent, weighed over 

 4,000 grams, and of this number 154 were males and 98 females. Only 8 weighed over 

 5,000 grams, and of this number 7 were males and 1 a female, 6 wore white and 2 black. 

 The total number of cases which were 52 cm. long and over, out of a series of 2,307 of both 

 races and sexes, was 415, or 17.9 per cent, Of these, 262 were males, 153 females, 287 

 white, and 128 black. 



Of 2,092 cases with a given duration of over nine month* [252 days) the heaviest was a 

 white male 49 cm. long, with a duration of 261 days and a weight of 7,545 grams, but the 

 longest, on the contrary, was a white female weighing 4,035 grams, with a duration of 287 

 days and a length of 59 cm. The shortest was a male negro measuring 21 cm., with a dura- 

 tion of 266 days and a weight of 2,920 grams. The shortest Caucasian was a female 40 

 cm. long, weighing 2,450 grams and having a duration of 275 days. The lightest of all 

 cases was a white female, with a length of 41 cm., a duration of 256 days, and a weight of 

 1,295 grams. The heaviest negro was a female 52 cm. long, with 316 days duration and a 

 weight of 5,556 grams. The longest negro was likewise a female, weighing 4, 1 95 grams, with 

 a length of 57.75 cm. and a duration of 306 days. 



From these figures it will be seen that the fluctuations in weight amounted to 113.5 

 per cent of the weight of the lightest and 31.8 per cent of that of the heaviest. The shortest 

 fetus, which was only 51.3 per cent as long as the lightest, nevertheless weighed 208.5 per 

 cent of the latter. Similarly, the fluctuation between the shortest and longest fetuses was 

 equal to 17.4 per cent of the former and 63.1 per cent of the latter. 



It is interesting to compare the fluctuations in weight in these cases with those existing 

 between twins of the same and of different pregnancies, even if the results in the one case 

 can not be considered confirmatory of those in the other. Because peculiar circulatory 

 conditions may exist in case of multiple pregnancy, one might expect to find greater varia- 

 tions in these cases, but such is not the fact in this series, at least. The greatest difference 

 in the lengths of practically full-term twins (250 and 266 days) from the same pregnancy 

 was 5 cm., or 11.6 per cent of the length of the shorter in two instances. The difference 

 in weights between the individuals of these respective pairs was equal to 330 grams, or 14.9 

 per cent of the weight of the fighter in case of the younger pair of female twins and 690.4 

 grams or 30.4 per cent of the weight of the lighter of the older pair of male twins. How- 

 ever, these differences are not the maximum differences noticed between individuals of the 

 same pair, for the length and weight of the male of much younger twins were 42 cm. and 1 ,6S0 

 grams respectively, and the corresponding measurements of the female were 36 cm. and 

 1,285 grams. Hence, in this pair the difference in length was 16.6 per cent of the length 

 of the shorter and the difference in weight was 30.7+ per cent of that of the lighter. 



The weight of the heaviest twin was 3,882.4 grams and that of its mate (which was 

 also a female) was 3,402 grams. If we contrast with this the weight of the lightest twin 

 over 252 days or 9 months old (which was 2,052 grams) and that of its female companion 

 (which was 2,685 grams), we see that the difference in weight between full-term twins is 

 89.2 per cent of that of the lightest, while the greatest difference in length was 27.5 per cent 

 of the length of the shortest, which was 40 cm. long. It is also interesting to note that the 

 two longest twins, which measure 51 cm. each, are exceeded in weight by several which are 

 only 44.5 cm. long. From these things it is evident that the fluctuation in the size of 

 twins, at large, both in length and weight, is considerably less than in the case of single 

 births. In the latter the maximum weight differences amounted to 113.5 per cent of the 

 lightest as compared with 89.2 per cent in the case of twins. Similarly, the maximum 

 differences in length amounted to 171.4 per cent of the length of the shortest in case of 



