This section is from the book "British Dogs: Their Varieties, History, Characteristics, Breeding, Management, And Exhibition", by Hugh Dalziel. Also available from Amazon: British Dogs.
Some score years ago a large proportion of the black and tan toy terriers were of the sort called by "fanciers" apple-headed ones - that is, round skulled with prominent foreheads - and this variety owed the features referred to to a cross with the King Charles spaniel.
Another variety, finer in the head and generally showing the wheel back and tucked-up flank of the Italian greyhound, owed its peculiar features to a cross with the last named dog.
Both of these have now, however, given place entirely, or to a great extent, to a much neater animal, showing truer terrier character, being, in fact, the Manchester, or black and tan terrier, dwarfed by constant selection of the smallest, and continued in-and-in breeding.
This continued consanguineous breeding is not, however, an unmixed good, and in some instances appears to have already been carried to the utmost brink it can be with safety, great delicacy of constitution being one result, and another is the loss of hair; many specimens being almost bare on head, face, and neck.
This is a great disfigurement which can be permanently remedied by judicious breeding. I have, however, in another breed lately found astonishing results in the quick growth of hair by rubbing in twice a day a mixture in equal parts of petroline - such as is burned in lamps with wick - the oil, not the spirit, Field's ozokerine, and the lotion, Spratt's patent make for growing hair on dogs. As the use of this mixture was eminently successful, I think it is worth mentioning that others may try it.
The points are the same as in the larger breed, and to that standard readers are referred. There is more difficulty experienced in producing a good one, well marked and rich in colour of the desired size, which is from 31b. to 51b. at most than there is in breeding dogs 201b. and over.
As they are thin in the skin and but lightly covered with hair, these fragile creatures should be kept clothed when out of doors.