PSOROPTIC MANGE — SHEEP SCAB. 623 



with some fatty substance, such as vaseline or oil, in order to guard 

 against the astringent action of the liquid. 



Each sheep is plunged in the bath for one or two minutes, or five 

 minutes at the most. All the diseased spots must be brushed, rubbed 

 and cleansed ; but care must be taken not to make them bleed. 



Tessier suggested leaving the animals for twenty-four hours in 

 some disinfected place, without straw or food, to prevent these 

 materials from being wetted by the liquid which runs from the 

 fleece, and which, if afterwards eaten, might have a poisonous effect. 

 Here, again, the danger has been exaggerated. Delafond has shown 

 that sheep may be given a fluid ounce of Tessier's bath for eight days 

 running without producing the slightest unfavourable symptom. 



Tessier's bath is excellent from the therapeutic standpoint, but it 

 imparts a yellow tint to the fleece, which is thus rendered less valuable. 

 The mixture has therefore been modified in various ways. 



Clement's Bath (1846). 



/ Arsenious acid . . . . . . 1'5 parts or lbs. 



For 100 sheep . . . . J Sulphate of zinc. . . . . . 5 ,, 



( Water 100 



In this bath every quart contains about 2^ drachms of arsenious 

 acid. Its toxic power, therefore, is considerably greater than that of 

 Tessier's bath. 



Clement's formula has one drawback. The sulphate of zinc may 

 be mistaken for a non- astringent alkaline sulphate (sulphate of soda), 

 and as a consequence poisoning may occur, as experience has shown. 



Mathieu of Sevres replaced the sulphate of iron by an equal 

 quantity of alum. In this case, each quart of the bath contains 

 2^ drachms of arsenious acid. 



Clement's and Mathieu's formulfe have given just as good results 

 as Tessier's. 



A last formula is that of Professor Trasbot. The aloes is of very 

 little use, however, because it is almost insoluble. 



For 100 sheep 



Arsenious acid . . . . . . . . 2 lbs. 



Sulphate of zinc . . . . . . 10 ,, 



Aloes . . . . . . . . . • 1 ,, 



^ Water 25 gallons. 



Condition of the animals after the hath.— On leaving the bath 

 the abraded parts are slightly cauterised. During the five or six 

 following days the skin is stiff, and covered with adherent crusts 

 over the points attacked by the parasites. The animals no longer 

 scratch or bite theinselves. 



