NATURK AND OUIC.IX OF VAIUOLA. Gl 



fever of an infectious and contagious kind*." This 

 description may be considered as equally correct when 

 applied to sheep-pox. 



That variola does not shew precisely the same 

 local effects in the sheep as in man, we admit, imd, 

 indeed, its progress and symptoms vary in the different 

 domesticated animals ; but these diversities are rather 

 to be referred to the special arrangement and develop- 

 ment of the component parts of the integument than to 

 any real change in the nature of the malady. That 

 these diverse appearances are but modifications of the 

 same affection is further proved by the fact, that the 

 causes which produce, and the laws which govern, the 

 extension of small-pox, both in man and in the inferior 

 creatures, are identical. 



Varieties in structure produce varieties in function, 

 both in health and disease ; and although the uses of 

 a part depend chiefly on its organism, may not these 

 be modified or influenced by many other circum- 

 stances, such as the climate an animal inhabits, its food, 

 temperament, and condition ? Some creatures have 

 their entire bodies covered with hair; others receive 

 but a partial covering of it: some are clothed with 

 wool, and others again with a mixture of both these 

 products of the skin. Some are flesh-eaters; others 

 feed on vegetables ; while there are those which subsist 

 on both. Some inhabit warm and dry, others cold 

 and humid localities. Some endure great privations 

 at the same time that their physical powers are being 

 heavily taxed ; while others are kept in a state of rest, 

 and largely supplied with different kinds of provender, 



* A Practical and Theoretical Treatise on Diseases of the Skin, 

 p. 49. London, 1842. 



