128 PHII.OS01'HICAL THANSACTIONS. [aNNO 1786. 



found that 18 were of the male and g of the female sex; and that the average 

 weight of the former was about 61b. 9 oz., that of the latter about 6 lb. 2 oz. 

 2 dr. Whether he, says Dr. Clarke, used the same weights, I cannot exactly 

 say. He observes, that he used the civil pound of Gottingen, which I can easily 

 perceive consisted of 16 oz. as mine did; but whether a German oz. be the same 

 with ours, I have not data to determine. The average length of the males mea- 

 sured by him was about 204- inches, and of the females about lQ-{^. He weighed 

 also the placentae of 21 lying-in women, 16 of whom had borne male children, 

 and 5 female. The average weight of the former was 1 lb. 2^ oz. ; that of the 

 latter 1 lb. 2 oz. Hence it appears, that in other circumstances, besides those I 

 have taken notice of, the male and female sex differ. So far I thought it neces- 

 sary to take extracts from Dr. Roederer's paper, as his observations and mine 

 throw light on each other, and add confirmation to both. 



There is one circumstance or two so intimately connected with his former 

 letter, that Dr. C. cannot pass them over in silence. Having found that males 

 suffer more in the birth than females, he was desirous of knowing whether the 

 chance of the mother's recovery was thereby in any degree affected; and to de- 

 termine this he was once more at the pains of turning over the registry with care. 

 He found, that of 214 women, dead of single children, 50 were delivered of 

 still-born males, and 15 of still-born females; 76 of living males, and 73 of 

 living females. Of the 1 5 dead of twins, 6 had twins one of each sex ; 6 others 

 had twins both of the male sex; and 3 had twins both of the female sex. All 

 of which twins (2 or 3 excepted) it is very remarkable, survived the death of 

 their mothers. It would appear then, that the life of the mother is principally 

 endangered in those cases where the bulk of the male's head precludes the pos- 

 sibility of his being brought into the world alive, either by the efforts of nature 

 or art. The conception of twins we have observed to be more fatal to the mo- 

 ther than that of single children. The average weight of 1 2 twins, which had 

 occurred to him of late, he found to be 11 lb. a pair. The largest pair weighed 

 13 lb. and the least 84-. From some rude attempts made to ascertain the weight 

 of the contents of the gravid uterus in cases of twin and single children, he was 

 inclined to think, that they ate to each other as about 15 to 10, or perhaps 144^ 



