394 • Duplicate Twins and Double Monsters 



case like the second one of Schnltze in which each individual had its own 

 cliorion, amnion and placenta, and in which both sexes were represented 

 [fraternal type]. In a case of quintuplets (Schultze) the five individu- 

 als were divided into two groups, one of three and the other of two, each 

 group with one placenta and a single amnion. [Probably a set of twins 

 and a set of triplets, each of the duplicate type, and bom at the same 

 time, i. e., the groups were fraternally related. The fact of the enclo- 

 sure of the members of each group within a single amnion interprets this 

 as two simultaneous instances of Case IV, and suggests the danger of 

 the fusion of the individuals of each group into a composite monster, 

 owing to the necessary proximity of the embryonal areas.] 



Concerning the possibility of sex in multiple births, it is evident mathe- 

 matically that triplets must be either of the same sex or else two must 

 be of one and one of the other. None of these cases postulate much 

 concerning the intra-uterine conditions or the type of individual, except 

 that where both sexes are represented, they cannot all be of the duplicate 

 type. In such a case the two that are of the same sex may be duplicates 

 or not. In c|uadruplets, of which reference to 72 cases is found in the 

 Index Catalogue of the Surgeon-General's Library at Washington (Gould 

 and Pyle) the case becomes still more complicated and practically nothing 

 can be postulated from sex data alone save a certain number of proba- 

 Ijilities. In one case, for instance, two girls possessed a single placenta 

 between them while the two others, apparently girls also, had each her 

 own placenta. Here little can be told owing to the insufficiency of data, 

 but it may be surmised that the first two were duplicate and the last two 

 fraternal. Another case reported in which there were two boys and two 

 girls, all united to one placenta, is a little difficult to classify, but the 

 union of placentfe may have been due in part to the close approximation, 

 and it is possible to consider the case one of two sets of duplicates, related 

 set to set as in Case II. 



As regards quintuplets, I have seen reports of the following combina- 

 tions of sexes, although the other data were insufficient to draw any con- 

 elusions whatever: ?$?$?, ^^S^% c?c^c???, ???J'(^- 



In each of two cases of sextuplets there were four boys and two girls 

 and in at least one of these (Vasalli, 88) there was a common placenta 

 for all. In the only autlientic case of octuplets which I have been able 

 to find (Boston Med. and Surg. Journal, Sept. 26, 1873) there were 

 five boys and three girls. 



Concerning the third set of data, that of physical identity, although 

 of extreme importance in the present argument, no mention is made in 

 any of the cases above quoted, evidently because they were the reports of 



