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SCIENCE 



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



function. This equality of size and func- 

 tion comes from the laws of growth; when 

 a unit increases in size so that the length of 

 its capillaries increases beyond the norm, a 

 new artery develops, the single unit split- 

 ting into two. 



In his study on the spleen Dr. Mall brings 

 out best the relation of all the tissues of an 

 organ to its function. Thus he showed by 

 experiments that the vessels of the spleen 

 are emptied by the contraction of the bands 

 of muscle on the trabeculae and that the 

 fibers of these same trabeculae are so ar- 

 ranged as to distend the veins and compress 

 the arteries as the muscles contract. 



One of his valuable contributions is the 

 study of the structure of the heart. He 

 grasped the significance of the work of 

 Krehl, which he said bore the stamp of Lud- 

 wig. In this work it is to be seen that the 

 atrio-ventricular rings are tendons of origin 

 for the bands of heart-muscle. In 1900 he 

 gave the study of the bands of heart-muscle 

 to John Bruce MacCallum, who unraveled 

 the ventricles of the heart in the embryo 

 pig into superficial and deep spiral bands 

 with their origin and insertion in two ten- 

 dons, the atrio-ventricular rings and the 

 chordae tendineae. As a tribute to this 

 brilliant work, Dr. Mall completed the 

 study on the adult human heart after Mac- 

 Callum 's death, reducing the problem to 

 the following simple terms : To understand 

 the beat of the heart one must figure out 

 how a muscular bag is constructed so as to 

 empty itself. We have Dr. Mall's speci- 

 mens in the laboratory showing how the 

 spiral bands contract with each beat of the 

 heart in the exact familiar pattern of 

 wringing out a rag. 



Another line of work which interested 

 him greatly was the study of the brain. 

 Here he was drawn to the anthropological 

 side. Dr. Hrdlicka, the anthropologist in 

 "Washington, had said to him that the brain 



of a negro could be distinguished from that 

 of a white man and with this in mind Dr. 

 Mall made a comparative study of the 

 brains in the anatomical collection, compar- 

 ing them by weights, the complexity of 

 their convolutions and other criteria. Real- 

 izing that no man can free himself of prej- 

 udice, he charted all of his data by means 

 of numbers, filling in the race and sex only 

 after the charts were complete. In this way 

 he showed that the crude, present-day meth- 

 ods are inadequate for scientific deductions 

 regarding the relation of the brain to race 

 and sex. Of the criteria on race, there re- 

 mains only the difference in the shape of 

 the brain corresponding to the well-known 

 shape of the head. 



In his anatomical studies Dr. Mall has 

 enriched his science with a wide range of 

 methods. Our laboratory is full of ex- 

 amples of beautiful injections, corrosions of 

 blood vessels, preparations of connective 

 tissue made by maceration, cleared embryos 

 to show the development of the skeleton 

 and many others. His own methods of 

 work in the laboratory are of great interest 

 and he frequently discussed the influence 

 of Ludwig in this connection. Contrary to 

 the usual type. Dr. Mall was far more ac- 

 tive mentally than physically. I have 

 known him to think and plan with the 

 greatest care so that a bit of routine might 

 be simplified. Thus it was his habit to 

 think out every detail of an experiment be- 

 fore he undertook it; he never employed 

 the system of trying a thing out without 

 adequate preparation or of approximating 

 his methods through errors. For this rea- 

 son he made but one experiment a day. If 

 it failed, he would not repeat it until the 

 .next day, thus giving himself ample time 

 to think out the reasons of his failure. 

 , He was intolerant of the collection of 

 unanalyzed material. His interest in tech- 

 nical procedures was only in their bearing 



