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SCIENCE 



[N. S. Vol. XLVII. No. 1211 



with more specimens, but not analyzed with 

 more insight. I recall in connection with 

 these more elaborate subsequent studies on 

 this subject, one of Dr. Mall's characteris- 

 tic comments : "I can never become in- 

 terested in the mere collection of new ex- 

 amples after a principle has once been 

 thoroughly established." In connection 

 with the study of the development of the 

 vascular system the two lines of thought 

 embodied in Dr. Mall's earlier work con- 

 verge. These two generalizations I under- 

 stand to be, first, that he approached anat- 

 omy from the standpoint of how structure 

 is adapted to function, a different idea from 

 that of the study of pure morphology, and 

 secondly, that he saw the value of organo- 

 genesis to the study of anatomy. He car- 

 ried over to embryology the methods of in- 

 jecting blood-vessels and lymphatics in use 

 for the adult and thereby made possible a 

 complete account of the spread of vessels in 

 the embryo. In the study of the vascular 

 system he emphasized again and again the 

 value of the study of an organ as a whole. 

 ,Trained by the man who invented the mi- 

 crotome and himself making many improve- 

 ments on it, he reacted strongly against 

 those anatomists who study only sections. 

 He was interested in the architecture of an 

 organ ; to use one of his own phrases he had 

 "a feeling for structure." Indeed, he has 

 often said that if he were to choose a career 

 again, it would be that of an architect. 

 His gift in anatomy, like the gift of the 

 sculptor or the architect, was the power to 

 visualize structure in three dimensions. 

 Thus, one can understand his pleasure in 

 the studies of the architecture of the vessels 

 of organs, given not in indefinite terms, but 

 showing the exact pattern of all vessels, 

 the number and the relations of the orders 

 of arteries from the main to the terminal 

 branches. Thus he has left us a rich heri- 

 tage of corrosions of the vessels of various 



organs which is worthy of a place in the 

 great scientific museums of the world. 



During the later years of his life. Dr. 

 Mall became more and more interested in 

 the problems associated with his collection ; 

 that is to say, in the type of problems for 

 which institutes for research are founded, 

 those that depend upon that analysis of 

 large amounts of material and the coopera- 

 tion of experts along closely allied lines. 

 These problems touch more and more closely 

 clinical medicine and social welfare. Such, 

 for example, is the study of abnormal em- 

 bryos, leading up to the analysis of their 

 frequency and causes, the normal curve of 

 growth, the determination of the age of the 

 embryo and the causes of sterility and abor- 

 tion. He first became interested in the 

 study of abnormal embryos through sepa- 

 rating the normal from the abnormal in his 

 collection. His first general account of ab- 

 normal embryos was in the volume of the 

 Johns Hopkins Hospital Eeports published 

 in honor of Dr. "Welch in 1900. Bight years 

 later he published a monograph on mon- 

 sters, of which Morgan wrote : 



The recent publication by Mall on the causes 

 underlying the origin of human monsters marks an 

 epoch in the study of teratology in this country, 

 for he has treated the subject with a breadth of 

 view and a wealth of illustration rarely found in 

 the handling of this complex question. Mail has 

 brought to the task a profound knowledge of the 

 older literature of the subject, an appreciation of 

 the most modern results in experimental teratol- 

 ogy, and a thorough familiarity at first hand with 

 the subject of human monsters. The physician and 

 anatomist are brought into close touch with work 

 generally supposed to be outside their proper 

 field; and on the other hand, the student of mal- 

 formations in the lower animals wiE be made to 

 appreciate the inexhaustible supply of human ma- 

 terials with which the anatomist and physician are 

 familiar. 



In this study and during the last six 

 years. Dr. Mall has given a masterly analy- 

 sis of the causes of monsters. He has shown 



