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VIII. — On the Hereditary Diseases of Horses, By Finlay Dun, 

 Jun., V.S., Lecturer on Materia Medica, &c., at the Edin- 

 burgh Veterinary College. 



Prize Essay. 



Our everyday experience of the production and development 

 of plants and animals at once suggests the existence of the 

 great natural law embodied in the familiar saying, " like pro- 

 duces like." In accordance with this law the peculiar proper- 

 ties, characters, and qualities of the parent — whether good or 

 bad, healthy or diseased, external or internal — are transmitted 

 to the offspring, or, in a word, are hereditary. To illustrate this 

 natural law of hereditary transmission, with especial reference 

 to the diseases of horses and cattle, is the object of this report, 

 and, in treating of the subject, we shall notice — 



I. General hereditary characters, both healthy and diseased, 

 II. The hereditary diseases of horses. 

 III. The hereditary diseases of cattle. 



I. Many interesting and valuable facts have been recorded 

 which prove, beyond all doubt, the hereditary tendency of many of 

 the physical, mental, and moral qualities of man. Parents transmit 

 to their children their own — or, at all events, similar — external 

 forms, similar intellectual capacities, temperaments, dispositions, 

 virtues, and vices, as well as similar tendencies to particular 

 diseases. Certain families are remarkable, during many centuries, 

 for tall and handsome figures, and for a striking similarity of 

 features ; whilst others perpetuate a less perfect form, the peculiar 

 deformities of the parents reappearing in the children of each 

 successive generation. For example, the thick upper lip of the 

 members of the imperial house of Austria has been a character- 

 istic of the family for centuries ; and every one is familiar with 

 the curious case of the Yorkshire family with their six fingers 

 and toes, which remarkable conformation has continued for 

 several generations ; and other analogous cases are recorded.* 

 But the hereditary transmission of external form is exemplified, 

 on a more extended scale, by the striking resemblance often 

 observed amongst the different individuals of a community 

 or race, even where these are exposed to different external 

 agencies. The cases of the Jews and the Gipsies will suggest 



* ' Researches into the Physical History of Mankind,' by James C. Prichard, 

 3rd edition, pp. 244-5. See also, at pp. 347-9, the description of a man whose 

 skin was greatly thickened and covered with warty excrescences, and in whose 

 descendants these peculiarities were noticeable in the third generation. 



