March 15, 1918] 



SCIENCE 



259 



that from the earliest ages of the world's 

 history the study of monsters has been one 

 of the capital problems of anatomy, medi- 

 cine and natural history ; that the belief in 

 supernatural causes gave way to the theory 

 of maternal impressions, and that this must 

 now give way to a scientific analysis of 

 their causes. Dr. Mall recognized that a 

 few abnormalities, polydactj'ly, for ex- 

 ample, are germinal and can not be pro- 

 duced experimentally; but that monsters 

 are not due to germinal or hereditary 

 causes, but are produced from normal em- 

 brj-os by influences which are to be sought 

 in their environment. The cause of mon- 

 sters, he has indicated, lies buried in the 

 non-committal term of faulty implantation. 

 In his recent paper on cyclopia he has fully 

 analyzed the meaning of recent experi- 

 mental embryology. He showed that as 

 soon as Stockard succeeded in experiment- 

 ing with eggs in such a way as to produce 

 cyclopian monsters at will, the explanation 

 of the process was at hand, for the work 

 demonstrated that a slight change in chem- 

 ical environment, acting at a critical time, 

 caused cyclopia. Dr. Mall studied the cj^- 

 clopian monsters in his collection, one of 

 which is at a stage where a complete analy- 

 sis could be made, and in conclusion he 

 says: 



It seems to me that the studies based upon our 

 collection of embryos, as well as recent investiga- 

 tions in experimental embryology, set at rest for 

 all time the question of the causation of monsters. 

 It has been my aim to demonstrate that the em- 

 bryos found in pathological human ova and those 

 obtained experimentally in animals are not analo- 

 gous or similar, but identical. A double monster or 

 a cyclopian fish is identical with the same condi- 

 tion in human beings. In all cases monsters are 

 produced by external causes acting upon the ovum. 



Thus, most localized abnormalities and 

 monsters, of which he gives a wealth of il- 

 lustrations, can be traced back to the faulty 

 nutrition of the embryo at early critical 



stages, and ths effects can be followed with 

 every grade of intensity, from complete de- 

 generation of the ovum to monsters which 

 survive to term. One of his most interest- 

 ing deductions is that in some forms of 

 fault}- implantation there results a disso- 

 ciation of the tissues of the embrj'o, so that 

 they grow exactly as do the cells in the 

 experiments with tissue cultures, without 

 the correlating forces which check and 

 integrate the organs in normal develop- 

 ment. It is to my mind a significant ex- 

 ample that this work has been carried on 

 during the years given to the organization 

 of a new institute, that is to say that Dr. 

 Mall so planned the work of administration 

 that it did not check research. It is not 

 too much to say that this work of Dr. 

 Mall 's opens up a new field, and that it has 

 already formed a broad foundation on 

 which all future study of abnormalities 

 must rest. Such was the work with which 

 he was engaged at the time of his death. 

 In his vision of an institute for embryolog- 

 ical research, he saw that the two great lines 

 of work in which he was most interested 

 could be brought to a successful conclusion 

 within a reasonable limit of time. First, that 

 the full development of the study of organo- 

 genesis could give us a completely ration- 

 alized anatomy; second, that there is a 

 group of problems such as the determina- 

 tion of the curve of growth, the study of 

 abnormalities and their causes, normal and 

 abnormal implantation which may perhaps 

 be brought together under the heading of 

 the study of the laws of growth, which lie 

 beyond the powers of a single individual 

 and thus must be attacked through or- 

 ganized research. Often he said during the 

 latter months of his life: "My work is 

 mapped out for the next ten years." For- 

 tunately in his "Plea for an institute of 

 human embryology" and in some unpub- 

 lished manuscripts some of these plans are 



