SHEEP SCAB. 
7 
shown in Figure I., 6. The eggs are white or whitish-translu- 
cent in color, about twice as long as broad and very large as 
compared with the mites. They are about four-tenths the length 
of the mature female and eight of them would entirely cover 
her body. They are deposited upon the surface of the skin 
of the sheep and not upon the wool. They stick readily to 
anything that touches them, especially to wool, so they are 
not readily lost from the sheep if anything should dislodge them 
from the skin. 
EXPERIMENTS FOR THE DESTRUCTION OF THE MITES AND 
THEIR EGGS— NOTES ON SUBSTANCES USED. 
The following substances were all used for the destruction 
of the mites or their eggs in the laboratory, but only the first 
ten were applied to sheep. 
*The Fort Collins Lime and Sulphur Dip — I have called this 
the Fort Collins dip because I know of no name previously 
given to lime and sulphur dip used in the same proportions. It 
contains lime, eleven pounds; sulphur, thirty-three pounds to 
100 gallons of water. The lime and sulphur are first thoroughly 
mixed in a small amount of water and boiled for about two 
hours and then diluted to 100 gallons and used at about 110 
degrees temperature. In my experiments the temperature was 
only about 90 degrees, and the sheep were kept in two minutes. 
Dr. Headden, our station chemist, tells me that, if the lime 
is of good quality, it should take but one pound to cut four 
pounds of sulphur, and that it is the excess of lime used, or 
faulty preparation in the lime and sulphur dips that does the 
injury to the wool that is so often complained of. Mr. Drake 
tells me that there have been no complaints of injury to the 
sheep he has dipped in lime and sulphur. 
California Dip — Sulphur, 100 pounds; lime, twenty-five 
pounds; water to make 100 gallons. 
The lime and sulphur were first mixed in a small amount 
of water and boiled about two hours before using. 
Also used at one-half the above strength. 
Potassium Sulphide Dip — This substance was first suggested 
by Dr. Headden, who furnished me with a quantity of the crys- 
tals as purchased upon the market. These seemed less effectual 
*Mr. W. A. Drake, an extensive purchaser and feeder of sheep near Fort 
Collins, tells me that he has put 38,000 sheep through a dip prepared in this 
manner the past fall and winter, and in only one instance has fresh scab 
appeared when the sheep were twice dipped, and he thinks that due to putting 
a scabby sheep in the bunch after dipping. The sheep were kept in the vat 
only one-half minute. 
