VARIETIES OF MANKIND. 



1305 



tion. Now this has been attributed to the 

 free intermixture of differently-coloured pa- 

 rents, which tends to confuse the breeds, and 

 to merge those varieties which are artificially 

 kept up among domesticated races by the 

 matching of similar parents. But although 

 this cause doubtless operates, yet it is far 

 from being the whole truth ; for the converse 

 occurrence may take place in animals which 

 are in process of being reclaimed from their 

 wild state, under circumstances that forbid 

 the idea of any such- intermixture. Thus, 

 Mr. Bell informs us that an Australian bitch, 

 or dingo, had a litter of puppies, the father of 

 which was also of that breed ; both parents 

 had been taken in the wild state ; both were 

 of the uniform reddish-brown colour which 

 belongs to the race ; and the mother had never 

 bred before; but the young, bred in confine- 

 ment, and in a half-domesticated state, were 

 all more or less spotted.* Now, considering 

 the strong evidence which exists, that the 

 colour of the offspring, in animals in which 

 the hue is disposed to vary, may be affected 

 by a mental impression at the time of im- 

 pregnation f, it does not seem improbable that 

 various differences in the general condition of 

 a wild and of a domesticated animal, should 

 so affect the constitution of the latter, as to 

 occasion an amount of variation in its off- 

 spring which does not exist in the former. 

 The same general rule holds good in Plants. 

 The tendency to the (so called) spontaneous 

 production of varieties, is the greatest in those 

 species which are most susceptible of influence 

 by cultivation ; and those which are themselves 

 least changed by external conditions, are those 

 which are observed to transmit their distinc- 

 tive characters most constantly and uninter- 

 ruptedly from one generation to another. Fur- 

 ther, the influence of cultivation will sometimes 

 develop in the individual the very same de- 

 partures from the usual specific type, which 

 are, in other cases, 'spontaneously ' manifested 

 in the offspring of a common parent. Thus, 

 it is well known that, by cultivation, the prim- 

 rose may be converted into the polyanthus, 

 and the cowslip into the oxslip ; but the late 

 Dean of Manchester raised all these four 

 forms from the seeds of the same plant ; and 

 Professor Henslow has been equally suc- 

 cessful. 



Until the limits of this tendency to spon- 

 taneous variation have been determined, there- 

 fore, in each particular instance, no valid 

 specific distinctions can be erected. It hap- 

 pens, in certain groups, that a peculiarity, in 

 itself very trivial, is transmitted uninterrupt- 

 edly from one generation to another, with 

 such constancy and regularity as to justify us 

 in believing that it has been always manifested. 

 Thus many of the reputed specific differences 

 of Moths and Butterflies rest on no other 

 foundation, than the constant presence of a 

 certain spot on some part of their wings ; and 



* British Quadrupeds, 2d edit. p. 203. 



f See a valuable collection of such cases by Dr. 

 Harvey, in the Edinburgh Monthly Journal for 

 November, 1850. 



there are Felines, which agree so closely in the 

 structure of their skeletons as not to be dis- 

 tinguishable osteologically, and which are only 

 regarded as belonging to distinct species, be- 

 cause a certain stripe or spot, which uniformly 

 shows itself on the skin of one, is as uniformly 

 absent from that of the other. On the other 

 hand, we see, in all our domesticated races, 

 great diversities among the offspring of a 

 common parentage ; and these differences are 

 sometimes so marked, that if he had not 

 positive evidence of this common parentage, 

 the naturalist would undoubtedly be justified, 

 by the importance of the diversity, in the es- 

 tablishment of numerous specific types, when 

 he has really seen but a few of the varieties 

 into which one and the same may pass. 



Of this tendency to " spontaneous " varia- 

 tion, it may be remarked, further, that like the 

 variation which may be traced to external 

 conditions, it has its limits, and does not 

 really tend to confuse the boundaries of 

 species, although it may frequently show the 

 necessity for their extension. Thus, notwith- 

 standing the multitude of varieties of the 

 Apple and the Pear which we possess, and 

 notwithstanding the apparent triviality of the 

 specific distinction between them (this being 

 little else than the existence of a gritty centre 

 in the pear, which is absent in the apple), yet 

 we never find this distinction confounded by 

 the presence of the distinctive characters of 

 the pear in the descendant of an apple, or by 

 the absence of it in the descendant of a pear. 

 So we find that, notwithstanding the multi- 

 plication of breeds of dogs and horses, sheep 

 and oxen, pigs and poultry, they all retain the 

 characters by which their respective kinds are 

 distinguished from their congeners. There 

 is no tendency to an obliteration of the dis- 

 tinctions between a dog and a fox, or between 

 a horse and an ass ; but these distinctions are 

 perpetuated with the same regularity, that 

 marks the stripes of the leopard or the spots 

 on the wing of a moth. But, on the other 

 hand, by observation of the spontaneous 

 changes which particular tribes of plants or 

 animals are liable to exhibit, we are some- 

 times led to extend our ideas of the compre- 

 hensiveness of species, and to bring into the 

 same category forms which were previously 

 supposed to be distinct types. Thus, for 

 example, it is the opinion of many distin- 

 guished naturalists, that not only are all the 

 breeds of Dogs to be considered as consti- 

 tuting one species, but that this species must 

 also include the Wolf; or, in other words, 

 that the wolf and the dog are to be con- 

 sidered as collateral descendants from the 

 same original parents. We shall presently 

 examine more in detail the evidence on which 

 this belief is founded ; supposing it to be 

 correct, we are only required to enlarge our 

 idea of the comprehensiveness of the species 

 Canis lupus, which must then include all the 

 breeds of C. familiaris as its varieties ; and 

 none of them are in any more danger than 

 before, of being confounded with the fox or 

 the jackal. Until, however, the limits of 



