G. GENERAL NATURAL HISTORY AND ZOOLOGY. 321 



wrinkled egg should be watched for at terra time, and on 

 liberation (which might be assisted by the experimenter) 

 marked, for example, by the excision of the claws or tips of 

 one of the toes (varying the toe cut with the individual), while 

 those from smooth eggs could be allowed to remain unmuti- 

 lated. If the coincidence between the character of the esrGT 

 and the sex of the bird should then be confirmed invariably, 

 as alleged, in say a hundred cases, the demonstration of the 

 truth of the hypothesis w T ould be complete, and entirely re- 

 moved from the chance of irrelative or accidental coincidence. 

 The egg cases should be kept for future reference and obser- 

 vation. 



MENTAL ABILITY OF DIFFERENT RACES. 



As the result of a laborious experimental investigation 

 into the intellectual capacity and development of children of 

 different races inhabiting the island of Jamaica, Mr. Houzeau 

 concludes, first, that there is in each child a different degree 

 of intellectual proficiency, though these individual differences 

 are much less than might be anticipated ; second, that an un- 

 equal rate or speed of improvement does not belong espe- 

 cially to any race ; third, that the rate of improvement is 

 due almost entirely to home influence, namely, to the rela- 

 tive elevation of the parental circle in which the children 

 live. On the other hand, Mr. Lindsay concludes, as the re- 

 sult of his observations, that at or up to a certain age girls 

 are as quick as, or quicker than, boys, at learning or repeat- 

 ing lessons, but that female superiority, so far as it exists, is 

 usually confined to school life ; second, that up to a certain 

 point there is the closest parallelism between the mental en- 

 dowments of the human child and sundry other animals; ii 

 some cases, even, the comparison is in favor of the animals ; 

 and yet that we have no reason for supposing that any of 

 these will, at the best, ever attain to even the average of the 

 intellectual and moral development of man. 12 A, X., 272. 



ON THE EVAPORATION FROM THE HUMAN SKIN. 



In order to determine how far the exterior circumstances, 

 as temperature, moisture, the wind, etc., affect the quantity of 

 water that passes from the human system in the form of per- 

 spiration, an investigation has been made by Erismann, under 



O 2 



