496 THE POPULAR SCIENCE MONTHLY. 



the best tests of specific value next to genetic incapacity. The 

 assumption finds its greatest support in genesis among the higher 

 animals, and the most thoroughly differentiated species ; but the 

 whole subject becomes complicated as we descend in the organic 

 scale, and hybrids between what naturalists generally separate as 

 good species are far more frequently fertile among plants and 

 lower animals than was formerly supposed ; while physiological 

 selection, as we have just seen, may render genesis impossible, or 

 at least prevent it, between varieties and incipient species. In 

 this light, hybridity becomes an important factor in the modifica- 

 tion of species. Unnecessary importance has been given, in my 

 judgment, to the fact that domestic and wild species differ in 

 the fertility of their crosses. It is assumed, for instance, that all 

 the known breeds of domestic dogs would be fertile inter se and 

 produce fertile crosses. It seems to me, on the very face,' a pre- 

 posterous proposition, and that many of the breeds of domestic 

 dogs are as distinct specifically, and even generically, so far as 

 this test is concerned, as they are in structure and other charac- 

 teristics. Who, for instance, has ever known or heard of a cross 

 between a bull-dog and a lap-dog, or between a Newfoundland 

 and a black-and-tan ? The difference in size alone would seem to 

 render such a cross, if not a physiological or a physical, at least a 

 practical, imj^ossibility ; so that hybridity among domestic ani- 

 mals tends to essentially the same result as among wild animals, 

 and confirms its importance as a differentiating factor. 



[To be concluded.'\ 



THE STORY OF A SCHOOL. 



By JAMES JOHONNOT. 



IIST this age of wholesale educational machinery the faithful 

 record of any school, individual in its character, ought to be 

 of interest to all who seek better results in practical ability than 

 our present systems of instruction succeed in giving. But, when 

 the school departs widely from recognized standards, its record is 

 of double value, as calling in question' prevalent customs, and 

 affording a new criterion for the judgment of current methods. 

 The tendency of instruction is to become set in its ways. Teach- 

 ers follow precedent and reach formalism. 



But from time to time particular individuals are found who 

 ask the reason of this or that practice, and call in question its 

 value as a means of culture. Hence arose the " teachers' insti- 

 tutes " in this country. They were first organized in the State of 

 New York, in 1846. They grew naturally out of the progress in 



