254 The Progress of Zoology. 



Livingstone says, " On the Kalomo we met an elephant which 

 had no tusks — as rare a sight in Africa as one with tusks is in 

 Ceylon." So in the proportions of the beast it varies so much 

 that the rule that twice the circumference of the fore-foot equals 

 the height of the animal has many exceptions, and one measure- 

 ment is by no means a certain indication of the other. 



The facts accumulated by Darwin and his coadjutors in this 

 inquiry place the question of species in a very different light to 

 that in which it was regarded by Lamarck. External influences 

 and a power of adaptation to circumstances are terms that 

 sound well and promise much, but they come to little when 

 severely tested. Felix qui potuit rerum cognoscere causas. 

 If the wading birds have acquired long legs by treading tip- 

 toe on the muddy flats where they seek their food, how is it the 

 ostrich has not, during more than 3000 years, accomplished a 

 stretch of its wings ? for it flaps them fiercely enough during its 

 perambulations to cause growth if they were conformable to the 

 alleged law of modification by circumstances. The fancy pigeons, 

 which assume so many forms that we almost doubt at last if they 

 are pigeons, maintain the specific characters of the wing almost 

 unaltered. The ibis of to-day is the same in all its characters as 

 the ibis on the oldest Egyptian monuments ; the same is the 

 case with the African elephant as figured on ancient coins, and 

 it becomes now a question whether any departure from type 

 can long maintain its ground — whether, in fact, variation in a 

 marked degree is not the first step in the process of the extinc- 

 tion of the race in which the variation has occurred. The 

 turnip and the potato as now cultivated in our fields are 

 varieties secured by artificial selection, and they appear to be 

 fast declining in vigour, so much so that farmers are seeking 

 substitutes for both, to fill the places in the routine of tillage, 

 which they threaten soon to leave vacant. In these cases the 

 process of Nature seems to be only permissive as regards varie- 

 ties, and that but for a season; they must revert to type or 

 disappear. 



In the applications of zoology, especially in connection with 

 physiology, which is the key to zoological secrets, this question 

 of species has more than a technical value. The whole interests 

 of civilization are bound up with it. The patriarch Jacob was 

 evidently an adept in cross breeding and the selection of 

 races, and observed the law that " like produces like" with as 

 much discretion as Mr. Jonathan Webb, the modern master of 

 the art of sheep breeding. Dr. Beke, who has just traversed the 

 country where Jacob grew rich in tending Laban's flocks, 

 reports that " ring-straked, speckled, and grisled cattle" abound 

 there, and apparently within such a circumscribed range as to 

 render it probable that the race has maintained its integrity 



