A6 Hybridity in Animals. 
to his doctrine have been developed by the mere force of circum- 
stances, a tendency to progressive advancement from the simplest 
to the most perfect forms. And here we may inquire, if educa- 
tion and domesticity can so vary not only the instincts but the 
very proportions of anatomical structure in dogs, do we not 
realize in the theory of Lamarck, a law of nature which would 
with equal readiness explain the unlimited transmutation of spe- 
cies into each other? és 
But is it proved that all the domestic dogs are really derived 
from a single species? Here again we appeal to one of the latest 
and best authorities on this question—Charles Hamilton Smith, 
whose laborious researches have led him to the following conclu- 
sions that the parents of our domestic dogs are derived from 
several distinct species, which were constituted with faculties to 
intermix, and thus to produce the interminable varieties familiar 
the smallest number, six; in the wild species they are always in 
pairs, and they never vary in a species. . “ 'T'o what other cause, 
then, can we ascribe the anomaly in domestic dogs, so justly as 
to an intermixture of species ?” : | én 
The dogs that have become wild in Paraguay, always hunt.in 
packs, thus resuming the wolf-like instinct of their progenitors, 
Will it be said that this is a newly developed instinct? or is it 
not rather an old one that new wants have reproduced, 
_* Natural History of the Dog, in Naturalist’s Library, vol i, p. 104, et passim. 
The Canis venatica of Burchell, connects the dog with the hyena almost without 
an interyal. { Ibid, ii, p. 79. 
