Febbuabt 4, 1910] 



SCIENCE ~ 



177 



two points were brought very close to- 

 gether; on the average, the Papuans tested 

 excelled Europeans considerably in this 

 test. On the other hand, Indians and Fili- 

 pinos, and a few Africans and Ainu, tested 

 in the same manner^ seem not to differ per- 

 ceptibly from whites. 



The pain sense is a matter of some in- 

 terest, because of the fortitude or stolidity 

 displayed by some races towards physical 

 suffering. It may be, and has been con- 

 jectured, that the sense for pain is blunt 

 in these races, as it is known to be in some 

 individuals who have allowed themselves to 

 be burned without flinching, and performed 

 other feats of fortitude. The pain sense is 

 tested by applying gradually increasing 

 pressure to some portion of the skin, and 

 requiring the person tested to indicate 

 when he first begins to feel pain. Now, as 

 a matter of fact, the results of McDougall 

 on the Papuans, and those of Dr. Bruner 

 and myself on Indians, Filipinos, Africans 

 and Ainu, are in close agreement on this 

 point. Greater pressure on the skin is 

 needed to produce pain in each of these 

 races than in whites. This is the average 

 result, but in this test the distribution of 

 the cases is specially important. Though 

 most whites feel pain at or about a certain 

 small pressure, there is quite a respectable 

 minority who give no sign till much higher 

 pressures are reached, their results corre- 

 sponding very closely to those of the ma- 

 jority of Indians. And similarly, a minor- 

 ity of Indians feel pain at much lower 

 pressures than the bulk of their fellows, 

 falling into the ranks of the white man. 

 In each group, the distribution is bimodal, 

 or aggregated about two points instead of 

 one ; but whites are principally aggregated 

 about the lower center, and Indians and 

 other races about the higher center. Intro- 

 spection comes to our aid in explaining this 

 anomaly, for it shows that there is some 



difficulty in telling just when the pressure 

 becomes painful. If one is satisfied with 

 slight discomfort, a moderate pressure will 

 be enough; but if a sharp twinge is de- 

 manded, the pressure must be considerably 

 increased. Most whites, under the condi- 

 tions of the test, are satisfied with slight 

 discomfort, while my impression in watch- 

 ing the Indians was that they were waiting- 

 to be really hurt. The racial difference- 

 would accordingly be one in the conception 

 of pain, or in understanding the test,, 

 rather than in the pain sense. 



On the whole, the keenness of the senses- 

 seems to be about on a par in the various- 

 races of mankind. Differences exist among- 

 the members of any race, and it is not im- 

 probable that differences exist between the 

 averages of certain groups, especially when 

 these are small, isolated and much inbred. 

 Rivers has in fact found such small groups 

 differing considerably from whites in the 

 color sense. One such group showed no 

 eases of our eormnon color blindness or 

 red-green blindness, while another group 

 showed an unusually large percentage of 

 color-blind individuals. In the larger 

 groups, the percentage of the color-blind 

 is, very likely, about constant, though the 

 existing records tend to show a somewhat 

 lower proportion among Mongolians than 

 among whites. Very large numbers of in- 

 dividuals need, however, to be tested in 

 order to determine such a proportion 

 closely; even among Europeans, the pro- 

 portion can not yet be regarded as finally 

 established. One thing is definitely shown 

 by the tests that have been made for color 

 blindness in various races: no race, how- 

 ever primitive, has been discovered in 

 which red-green blindness was the uni- 

 versal or general condition; and this is a 

 fact of some interest in connection with the 

 physiology of color vision, for it seems 

 probable that red-green blindness, since it 



