be removed on to the paper. The scraped material should be placed in a small vessel, covered with a little 10 per cent. caustic potash solution, which is then raised just to the boil. This breaks up a great deal of the short hair and masses of cells which are present. Often if some of the material is examined at this stage between two slides or in a thin layer in a Petri dish the parasites will be discovered. It is, however, better to place the boiled material in a centrifuge tube, give it a few turns in the machine, then decant and examine a small quantity of the deposit between two slides under the inch lens.

There is possibly no other disease where success in treatment depends so much upon the personal element, more so probably in the case of the attendant than the veterinary surgeon. Where great numbers of animals. have to be treated, dips for liquid dressings or plants for generating sulphur dioxide are economical and successful. There are a great number of dressings suitable for general practice, and these fall roughly into two classes-viz., watery and oily or fatty; the latter is to be preferred.

The desiderata of a dressing are that (1) it will remain active and moist on the skin for some days; (2) it kills the parasites; (3) it is non-toxic; (4) it is fairly foolproof; (5) it is not prohibitive in price, and (6) does not mat, blister, or cake upon the skin. Probably a mixture of the following answers most of the above qualifications:

Strong calcium polysulphide solution
Water

Horse fat

I part

= 8 ounces

2 parts = 16
2 parts = 16

2 pints

The strong solution of calcium polysulphide can be prepared in small quantities by mixing 21 pounds of

sulphur with 1 pound of good quicklime in a bucket, make into a paste, and boil in 2 gallons of water until a dark red-brown solution is formed. Boiling will take about three hours; the whole must be kept well stirred during the process, and made up to 2 gallons at the end. About 2 pints of the oily mixture will dress a properly prepared ordinary case.

With care the following preparation may be used:

The following emulsion is very valuable in reliable hands, but careless use may lead to blistering:

When properly made by well mixing the oil into the hot soap solution a cream-like emulsion results.

Each of the above formulæ should be applied when at a temperature of about 110° F. The following routine may be followed:

First Day. Clip closely all over, even the mane and tail in some cases. No hair must be left long; if it is, matting and blistering will result later.

Second Day. Soak in warm water; incorporate soft soap. Wash and remove all epidermal accumulations by scraping. This is a most important operation; the water must not be above 120° F. or cracking of the skin occurs at a later date. Dry and exercise.

Third Day. Apply dressing all over, care being taken not to miss the submaxillary, axillary, and inguinal regions. The animal should not, however, be saturated. No bedding, no rugs.

Fourth, Fifth, Sixth, Seventh, and Eighth Days.—Move the dressing daily by firm rubbing with an oily rag,

and re-apply a very little dressing to dry affected areas. Exercise.

Ninth Day.-Wash, removing every vestige of dressing. Dry and exercise. Whilst this is being done the stall and head collar must be disinfected.

Tenth Day.-Groom hard; if necessary, re-clip and commence as from the third day. Three courses usually effect a cure, but it is a question of scrupulous attention to detail. Daily or every-other-day dressing often causes serious dermatitis, worse than the disease itself.

A great number of apparently cured cases recur; many of these are due to a small mange mite population being left upon the patient, and the disease breaks out again when they have become sufficiently numerous; others are due to re-infection from harness, brushes, or the stable. The "following up" of apparently cured mange cases by clipping and dressing with watery and less active parasiticides are important items in consecutive treatment. Although bland oils are often discarded in favour of watery dressings on account of the cost, their use would often be economically justified owing to the greatly reduced loss of working time resulting thereby.

CHAPTER III

FAMILY SARCOPTIDE (continued)

Genus Notadres Railliet 1893.

THIS genus closely resembles Sarcoptes, but differs from it by the important fact that the anus is on the dorsum. The species are generally much smaller than those of Sarcoptes. As a result of having long been included in genus Sarcoptes some confusion arises as to whether an animal is or is not liable to sarcoptic or notœdric mange.

Notadres cati (Hering 1838).

Syn.: Sarcoptes cati Hering 1838. S. minor Furstenberg 1861. S. notædres Megnin 1876. S. notædres var. cati Megnin 1880.

Body rounded in both sexes, no lateral depressions. Habitat, the head of the cat; the common cause of mange in this animal. It can often be easily found by soaking crusts in 10 per cent. caustic potash solution and pressing between two slides. The eggs are deposited in groups or nests. See Figs. 11 and 12. Measurements (Megnin):