186 Scientific Proceedings, Roi/al Dublin Society . 



colt. The same pale tint appears in a less degree ou the rump ; and in this 

 circumstance of the dun tint also she resembles the quagga.'" 



At the time this was held by Lord Morton and others to have been a 

 case of " infection of the germ " or telegony, as we now call it ; but, as early 

 as 1839, Dr. W. Maodonald, of Edinburgh, in a paper also read before the 

 Royal Society, doubted this explanation, and suggested that the chestnut 

 mare's foals were reversions. He pointed out that "similar markings are very 

 commonly met with on the Bel-back dun ponies of Scotland " ; and, as the 

 chestnut mare " was not pure, she may have inherited the tendency to those 

 peculiar markings." He observed further that the " cross-bar markings on 

 the legs [of the chestnut mare's foals] are not found in the quagga, but only 

 in the zebra, which is a species quite distinct from the quagga " — a fact which 

 he considers as completely overturning the reasoning by which the conclu- 

 sions stated in Lord Morton's paper were deduced. The facts, he thinks, 

 admit of a more natural explanation, and one more consistent with the 

 known physiological laws of development, by supposing the stain in the 

 purity of the mare's Arab blood to have arisen from the circumstance of au 

 early progenitor of the mare having belonged to the eel-backed dun variety, 

 the peculiarities of which appeared in a later generation.- 



Hamilton Smith, whose " Natural History of Horses " was published as 

 one of Jardine's " Naturalist's Library " in 1841, and whose knowledge 

 of the history and distribution of the horse was beyond that of such 

 contemporaries as Touatt and Low, thought Macdonald's " conjecture . . . 

 far-fetched."^ Yet he thought there was a possibility of the colours reverting. 

 He believed that horses were descended from five original stocks, viz., the bay, 

 the white or grey, the black, the dun or tan, and the tangum, piebald or 

 skewbald, which had been mingled together ; that, as a result of this mingling) 

 horses were now of many colours ; but that all tended to return to the original 

 five. His statement is worth quoting : — " From the different colours of the 

 original stocks, horses are clothed in a greater diversity of liveries than any 

 other animals, cattle and dogs not excepted ; they are a natural consequence of 

 interminable crossings of the five great stirpes already mentioned, producing 

 combinations which have caused French and Spanish writers to enumerate 

 above sixty : the piebald and dappled find only their counterparts in the 

 forms and shades of colour in some species of seals, and it is there also we 

 find the light blue greys with brown spots, of which we have examples in the 

 New Forest and in Spain : yet excepting the five primitive, all the rest have 



' Philosophical Transactions for 1821, p. 20. - Pioc. Royal Society, iv., p. 164. 



' "Natural History of Horses," p. 73. 



