110 



Dr. Van Es, while practicing in Mobile, reported to me 

 a case where a milker became infected on the hand by 

 milking cows with cow pox. 



Owing to the fact that man is inoculated (vaccinated) 

 with bovine virus (cow pox virus) to produce a partial 

 immunity to small pox, it is possible that many cows may 

 become inoculated by milkers who scratch their vac- 

 cinated arms and fail to disinfect their finger nails before 

 milking the cows. Records (Crookshank and others) 

 seem to indicate that cow pox is usually more prevalent 

 when small pox scares are numerous, and many persons 

 are vaccinated; this relationship appears to be true so 

 far as the imperfect records of cow pox in Alabama can 

 indicate. I have observed that children who drink raw 

 milk sometimes have ulcers not unlike vaccination ul- 

 cers, about the mouth or face or on the hands ; this might 

 result from scratching pimples, eroded places or sores 

 when the finger nails are covered with infected milk. 



The fact that milkers, who become infected with cow 

 pox, were partly or wholly immune to small pox, led the 

 celebrated Jenner to discover and apply the method of 

 vaccinating man with cow pox virus in order to prevent 

 virulent small pox. 



The virus of cow pox is fixed and can only be trans- 

 mitted by direct inoculation. Generally the milker car- 

 ries it from one cow to another and, if not immune, inoc- 

 ulates himself, or carries it from his vaccinated arm to a 

 susceptible cow. One attack, or series of eruptions, pro- 

 duces immunity in a cow for life. Hence young cows at 

 first period of lactation (with first calf) are the ones 

 most frequently infected; yet older cows may have it if 

 not already immune. It is generally more virulent in 

 winter than in summer. 



The chief troubles resulting from cow pox are the an- 

 noyance or difficulty in milking and sometimes a decrease 



