PREFATORY NOTE 



mated with precision the signification of paedomorphism as a sign not so 

 much of arrested as of incompleted development. 



Undoubtedly the most striking of the results demonstrated in the present 

 memoir, and that on which in conversation he laid the greatest stress, was in 

 his own words that "the differences between the crania are not due to race, 

 but to methods of living, and in some degree to differences of mental strength 

 in individuals." This modest statement by no means conveys the full import 

 of his demonstration. What his laborious, skilful, and accurate measure- 

 ments, taken in conjunction with the proved unity of race but diversity of 

 nutrition and culture-conditions of his specimens, show, is that the ordinary 

 contrasts in skull-forms, upon which many stately theories of races and 

 schemes of prehistoric interminglings have been erected, are of such minor 

 and doubtful significance that they are inadequate for that purpose. 



Pursuing this line of research further. Dr. Allen asked himself, What is 

 the proximate and remote etiology, what are the immediate and more distant 

 factors, in the modification of skull-forms ? In the present memoir he brings 

 out some of these with force, while others, which, had he lived, he would have 

 developed fully, are merely suggested. Thus, the correlation of the loss of 

 the upper front teeth with important variations in cranial conformation is ad- 

 mirably set forth ; and the influence of diseased action causing disuse, and 

 thus, in turn, lessening nutrition and modifying shape and contour, is clearly 

 explained. 



The tentative inquiries which he placed in the paragraph previous to 

 his " concluding remarks" were of far more weight in his own mind than his 

 expressions indicate. In the last conversation I had with him, a few days 

 before his decease, he asked my attention particularly to the consideration 

 whether the whole range of exanthemata, and especially measles, to which the 

 white race has been time out of mind exposed and is now largely immune, 

 are not chargeable with many of its peculiar characteristics in facial and 

 cranial anatomy. It was clearly his intention to present this from a much 

 wider comparative scheme than the present memoir permitted. 



He also almost incidentally refers in the present paper to a subject which 

 interested him deeply and on which he would have made more extended ex- 

 aminations ; that is, as above mentioned, the mental capacity of the individual 

 as a distinct cause of modified skull-form. While this in itself is not new, 

 he aimed to approach it by novel tests. 



The last lines of the memoir are indicative of his loftier estimate of 



