356 Harris Hawthorne \\ ilder 



ghetto among all sorts of malformations and deformities under the 

 general head of "teratology", an omnium gatherum in which a few have 

 sought and found valuable material but which for the most part have 

 been left to the curiosity-seekers. Indeed, with the exception of the 

 brilliant suggestion of Fisher^ who in 1866 separated the double mon- 

 sters from the rest, there has been little or no attempt to distinguish be- 

 tween monsters that develop in accordance with the laws of growth inher- 

 ent in the organism and the various deformities due to external causes. 

 Classifications of monsters are not wanting, indeed the earlier teratolo- 

 gists did little else but classify, each by his own method, but a careful dis- 

 tinction between the two sorts does not seem to have been made. 



That this distinction, that between an unusual form of development 

 and a deformity, is a real one, is easily shown. It takes but a moment's 

 consideration to see that such a case as that of the Siamese or other 

 conjoined twins does not belong in the same class with an acephalus, 

 or with a monster showing distortion or truncation of limbs, since the 

 former shows a perfectly normal development in respect to bodily sym- 

 metry and the normal condition of the organs and tissues. It is an 

 unusual type of being, but is not a deformity or malformation ; and from 

 this standpoint it is but a step to include also all double monsters 

 formed of equal components, the "diplopagi" of my previous paper 

 (1904). At that time I made a sharp distinction between those double 

 monsters in which the components are equal and those in which one com- 

 ponent is more or less reduced (i. e.. '"parasitic" monsters), but since 

 then I have changed my views on this point and include them with 

 equal diplopagi, a point concerning which I shall have something 

 to say later on. Passing this over for the present, however, I may say 

 that what I then recognized of the definiteness and order characterizing 

 the structure and development of diplopagi has been corroborated and 

 emphasized by the opportunities I have since had of investigating many 

 more cases, and their symmetry and regularity in anatomical details 

 have led me to insist upon a sharp distinction between them and other 

 forms of anomalies and to look upon the former as beings as orderly 

 and perfect in their development as are the usual and normal types of 

 being. AhnormM they certainly are in the sense of not being the usual 

 form in which a given species manifests itself, but they are not deformed. 



Furthermore, it seems also necessary to extend this distinction lietween 

 orderly and deformed beings so as to include, not only diplopagi with 

 both equal and unequal components, and normal individuals, but also 



