314 INFECTIVE DISEASES. 



Natural and Casual Cow-pox. 



To appreciate the characters of the natural disease in the cow, 

 we must dismiss from our minds the artificial disease vaccinia, for 

 the ordinary results of vaccination stand in much the same relation 

 to the natural disease cow-pox as the benign vesicle of variolation to 

 natviral smail-pox. 



The description of cow-pox given by Jenner, in 1798, was the 

 first published account. The disease in the cow was described as 

 consisting of irregular pustules on the teats, of a palish blue colour, 

 surrounded by an erysipelatous inflammation, and characterised by 

 a tendencj' to degenerate into phagedsenic ulcers. The animals were 

 indisposed and the secretion of milk lessened. 



In referring to an outbreak which occurred epizootically in 

 London in February 1799, Dr. Bradley gave a coloured plate of the 

 disease on the arm and fingers of a milker. The cow-pox, he said, 

 in this instance, " appears to have been very mild, for no loss was 

 experienced by the farmers from the deficiency of milk, as usually 

 happens." 



These early descriptions were supplemented by an account of 

 cow-pox by Mr. Lawrence, author of A Philosophical and Practical 

 Treatise on Horses, and on the Moral Duties of Man towm-d the Brute 

 Creation. Lawrence's article on cow-pox not only affords evidence 

 that this disease was known to those who had the care of cattle 

 before Jenner's paper was published, but it shows that it had also 

 been made the subject of practical observation and study by veteri- 

 narians. Lawrence concluded by saying : " Whatever may be the 

 fate of cow-pox inoculation, it has and will give further occasion to 

 a pretty large and open discussion, which is always beneficial as 

 having a tendency to produce discovery and promote improvement ; 

 and when the public ardour for the present topic shall have become 

 a little cool and satisfied, I hope it will be turned by enlightened 

 men towards another, perhaps of nearly as great consequence — 

 namely, the prevention of the original malady in the animals them- 

 selves. Those who have witnessed it and only reflected upon the 

 excessive filth and nastiness which must unavoidably mix with the 

 milk in an infected dairy of cows, and the corrupt and unsalubrious 

 state of their produce in consequence, will surely join me in that 

 sentiment." 



Lawrence was almost a century before his time. Cow-pox was not 

 again brought forward in this light until 1887-88, when the author 

 reported the contamination of the milk at the Wiltshire farms, and 



