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



single births, but only to 27.5 per cent in case of twins of different pregnancies and, of 

 course, much less in case of twins from the same pregnancy. The existence of such exceed- 

 ingly large and apparently normal fluctuations naturally necessitates the greatest caution 

 in the use of any curve of growth for the determination of the age of a fetus even in the 

 later months of pregnancy. It also enforces the necessity for a large basis if more than the 

 roughest kind of approximation is to be attained in the construction and use of curves of 

 growth. Moreover, it also justifies, it seems to me, the disregarding of far-outlying cases in 

 the construction of graphs representing the median. 



The above lack of correlation between weight and length recalls the observations of 

 Bonnet (1884 and 1889) on ruminants, especially the sheep, and also those of Lomer (1889), 

 who stated that it is surprising that two fetuses which may have the same length and 

 weight, equally long fingers, and equally sized eyes and ears, may nevertheless not infre- 

 quently have hearts of wholly different size. Or, on the contrary, the fact that three 

 fetuses whose body-weight varies by 1,000 grams may be found to have hearts of the same 

 size and weight. As might be expected from this, Lomer found similar variations in all 

 organs of the healthy fetal body. Moreover, it may be recalled that Oppel (1891) found 

 the same thing true in a number of vertebrates and that Keibel (1894 and 1895) called 

 attention to the occurrence of the same phenomenon in pigs. 



In reflecting upon the possible explanation for these things one is naturally led to think 

 of the internal secretions. As far as body-length and total weight are concerned the recent 

 work of dishing (1911) and others would seem to suggest a possible explanation for fetal 

 gigantism or obesity. However, such an explanation could scarcely hold for individual 

 organs, although there would, a priori, seem to be no reason why these could not be affected 

 individually as well as individual portions of the osseous system or the whole of it. Although 

 I do not wish to assume a causal relationship, I am also reminded in this connection that 

 some years since I noticed that many of the sheep fetuses of the third month, even, with 

 marked goiters, were very plump. However, since the basis of observation was very small, 

 I could only conclude that this was probably nothing more than a mere coincidence. 



Among the total 2,476 cases plotted — not all on any one chart — 318, or 12.8 per cent, 

 had a duration of 300 days and over. Hiibner (1913) found only 498 cases, or 3.2 per cent, 

 among a total of 2,000 births in Berlin with a duration of 302 to 324 days, while von Winkel 

 found only 3.3 per cent with a duration of 302 to 347 days among 1,702 cases in Dresden. 

 Of the above 318 cases 133 had a length of over 50 cm. or a weight over 4,000 grams. Among 

 these 133 there were 68 males with an average weight of 3,797.5 grams and an average 

 length of 52.6 cm., and 55 females with an average weight of 3,862.3 grams and a length of 

 52.2 cm. However, since only 55 of the 318 cases, or 17.2 per cent of those with a duration 

 of 300 days and over, had a length over 52 cm. and only 42 or 13.5 per cent weighed over 

 4,000 grams, it would seem that the duration of pregnancy must have been inaccurate — 

 i. e., alleged too long — in quite a large percentage of cases. This assumption is also con- 

 firmed by the character of the right extremity of the curve in figure 1, but seemingly con- 

 tradicted by the fact that Kaul (1912) found only 2.8 per cent of the new-born to weigh 

 4,000 grams and over in a total of 12,886 mature births at Breslau. Kaul also gives the 

 following percentages of heavy births for the following clinics: Dresden 2.76, Munich 3.45, 

 Bonn 4.76, Marburg 3.38, Leipzig 4.68, Kiel 8.31. The average percentage of heavy 

 fetuses in full-term pregnancies for a total of 78,352 cases in these cities, as calculated from 

 the figures given by Kaul, is 4.3. 



