360 BOVINE PATHOLOGY. 



tion of constitutional treatment is debated, but tbe 

 value of tonics, especially arsenic, cannot be questioned. 

 In this disease isolation must be enforced, all clotting 

 and appliances from the affected animal either destroyed 

 or thoroughly purified. 



Symhiotes hovis infests the region of the tail, is rare, 

 and must be treated like Dermatodectes. 



Phthieiasis — " Lousiness '' — is very common in cattle, 

 especially in marked cases of debility, whether due to 

 disease or to want of food and shelter (as in animals half- 

 starved in a straw yard) ; the lice abound, and cause 

 pruritus, and materially retard growth and development 

 of the stock. They prove troublesome to the auscultator 

 who has not remarked their presence. Several different 

 forms are described, as Hamatopinus vituli (which 

 specially affects the calf), and Harrii eurysternus, ani et 

 vulva, found on the cow, the former on the shoulders, 

 the latter in the positions which its name indicates. 

 Also, there is a form of Trichodectes present in some 

 cases. For the removal of these pests dressings with 

 tobacco water and stavesacre infusion are recommended. 

 These require to be several times repeated, well rubbed in, 

 and the animal should be subsequently thoroughly washed. 

 Measures should be taken to prevent their passage to man 

 or other animals. 



CEsTEiASis {'' Warhles'^), — CEstrus hovis, the gad-fly of 

 the ox, assumes its imago or perfect form at about the end 

 of summer ; it then attacks cattle, puncturing their skin 

 by means of an ovipositor, and placing in the subcutaneous 

 tissue a drop of acrid fluid with an ovum. There results 

 an abscess of small size with a larva situated in it. A 

 small opening extends from the surface to the abscess 

 cavity; against this the respiratory orifice of the grub is 

 placed, and he feeds upon the pus of the abscess. At 

 length the abscess bursts (according to Youatt, always 

 between the hours of six and eight in the morning), and 

 the larva falls to the ground and becomes a chrysalis, if 

 it escapes its numerous enemies, notably birds, who con- 

 sider it a sweet morsel. This occurs in about June or 



