280 ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 3 



the law of gravity ; if all exceptions were run to the ground and all 

 leads followed, the physical basis for these observations could in each 

 case be established, or the rule refuted. 



With man we have several advantages, and one disadvantage. We 

 are dealing with a single species, or rassenkreis, to use Rensch's term 

 (1929, 1936-37), that is extremely numerous for a mammal and that 

 covers a larger geographical area than that of almost any other 

 mammal. More human beings have been "collected'' than any otlier 

 kind of fauna. Our measurements, while far from adequate, are 

 relatively numerous. Another advantage is that we know quite a lot 

 about the history of man. One principal disadvantage is that man 

 possesses culture. In addition to his enormous capacity for physical 

 adjustment to many climates, he has developed artificial adaptive 

 aids, such as the use of fire, shelter, clothing, food preservation, and 

 transportation, which have permitted him to occupy every single part 

 of the land surface of the world except the Greenland and Antarctic 

 icecaps, and by means of which he is already looking for further 

 conquests in other planets and outer space. There neither Gloger, 

 nor Bergmann, nor Allen can help him. 



For the best part of a million years, some kind of man has existed, 

 probably occupying not one but several environments, and during his 

 evolutionary life span the climates of most, if not all, of the regions in 

 which he has lived have been altered, in most cases more than once. 

 As part of the cultural growth of man, two principal evolutionary 

 shifts have been achieved. The brain has gone through two major 

 changes in size, quite independently of body size,^ by means of two 

 consecutive doublings of the cortical area. This means that two major 

 steps in human evolution may have taken place since the ancestors of 

 man became erect bipedal primates feeding themselves with their 

 hands. This further means that some, if not all, of the climatically 

 adaptive changes which distinguish modern races from one another 

 may have been acquired in stage 1 — or stage 2 of this process, rather 

 than in stage 3, the modern level of potential cerebration. The late 

 Franz Weidenreich postulated (1943) that the Mongoloid face began 

 with Sinanthropus in stage 2. Whether or not he was correct, that 

 anatomist was prepared to accept the thesis of presapiens raciation, 

 and the concomitant thesis of multiple evolution from an earlier 

 evolutionary level. Wliether or not one or several human stocks made 

 this jump, we do not know, but for present purposes the latter pos- 

 sibility must be taken into consideration. 



We must not, however, assume that any or all stocks which passed 

 through the first two cerebral size stages to the third were any more 



"SchuUz, 1950, graph on p. 45. See also Bok, 1939; Bonln, 1937, 1938, 1950; 

 Danilewsky, 1880; Dubois, 1898'; Kraus, Davison, and Well, 19i28 ; Schepers, 1946; 

 Stiles, 1946 ; Van Dllla, Day, and Slple, 1®49. 



