THE SKIN 155 



and, not receiving their proper rest, they probably do 

 not do as well as they otherwise would. 



It is not a difficult matter to eradicate lice, but their 

 permanent elimination from swine entails continued 

 vigilance. Where large numbers of swine are infested 

 the most economical plan is to put in a dipping vat 

 and dip the hogs every ten days for three or four 

 dippings. In the meantime the sleeping quarters 

 should be cleaned and dipping solution used here 

 as a spray. If there are only a few swine to treat, 

 hand dressing with some standard dip is the most eco- 

 nomical method of treating them, of if the swine have a 

 tank or place where they wallow, some dipping solution 

 may be placed therein. The swine thus dip themselves 

 and destroy the lice. 



The rubbing post has been used with fair success as a 

 means of holding louse infection in check. One or more 

 posts are set in the pens and ropes wound tightly around 

 them for a distance of two feet from the ground. These 

 ropes should be moistened with crude petroleum from time 

 to time. The swine will annoint themselves and destroy 

 most of the lice by rubbing themselves against these posts. 



Mange 



Mange, or infestation of swine with some Acari or 

 mange parasites, is not a rare condition in this country, 

 where two forms of mange occur sarcoptic mange and 

 demodectic mange. 



Sarcoptic Mange 



Sarcoptic mange is enzootic in certain sections. It is 

 caused by infestation with the Sarcoptes scarbiei, var. 

 suis. The life cycle of this parasite is as follows: 



The ovigerous female burrows into the skin, forming 

 galleries in which she deposits her eggs, usually about fifteen 

 in number. The ova hatch in from five to ten days into 

 six-legged asexual larvae which may remain in the gal- 

 leries or pass out under the scabs, and in two to three 

 days moult into nymphse. The nymphse have four 



