POULTRY LOUSINESS IN THE HOUSE. 215 



ing it the aspect of tiger spots. In places where the erup- 

 tion has been the most confluent, the depilation spreads be- 

 tween the vesicles, and so extends over a considerable patch 

 of surface ; but, even in these places, the circular disposition 

 of the denuded patches, the primary expression of the origi- 

 nal vesicular eruption, is still maintained in the smooth con- 

 dition of the epidermis. 



"This depilation spreads, like the vesicular eruption of 

 which it is the consequence, with very great rapidity. In 

 two or three days the horse with the most shining coat may 

 have it spotted over with circular patches bare of hair, and in 

 the course of a week will the hair and epidermis be destroyed 

 over a large extent corresponding to the parts where the 

 eruption has been the most confluent. Such is the rapidity 

 of the depilation that we are but too apt to date the disease 

 back to a long period when it is, in truth, but of a few days' 

 duration. 



" It is only at this stage of the phthyriasis that horses 

 ordinarily come under observation ; and therefore does it be- 

 come difficult at such a time to assign to the disease any spe- 

 cific character : the vesicular kind of eruption serving to dis- 

 tinguish and classify it having left no trace upon the skin 

 save circular depilation. Sometimes, at this stage of the 

 disease, solid papulae form within the substance of the 

 skin, which become crowned with secondary vesicles, whose 

 progress is identical with that of those we have already 

 pointed out, disappearing after the formation and detach- 

 ment of the crust which succeeds the secretion. 



" During the whole of this stage, as at the first breaking out 

 of the disease, the patients are tormented with continual burn- 

 ing itching, causing them to rub themselves incessantly and 

 without relaxation; so that we observe upon the skin, in 

 those places the most rubbed, lesions, which we may call trau- 



