The breakdown of the plastic found in dolls of the 1940's and 1950's has been called "Pedigree disease" because it has been found in a number of hard plastic Pedigree dolls. This is an unfortunate name, since the problem is not confined to Pedigree dolls and it is definitely not a disease. It would be better known as "Plastic Breakdown".
The problem affects cellulose-acetate based plastics and includes films as well as dolls and other articles. As the plastic deteriorates, it produces a characteristic vinegar smell. The plastic dolls may develop unusual pink or dry grey patches. A brown liquid is often produced and in the final stages the plastic becomes warped and split.
The effects appear gradually, but once the reaction or "breakdown" has started, it cannot be reversed and the loss of the doll is inevitable. The vinegar smell is actually the acetic acid vapour given off during the decay process, and this may effect other nearby items. It could also be injurious to your eyes and skin, and children should not be allowed to play with affected dolls.
The problem is basically one of an unstable plastic compound and often only one arm or leg may be affected. However, any doll suffering from the problem should be isolated from others in the collection to avoid possible contamination. Storage in a low temperature and low humidity environment will slow the reaction and hopefully a solution to the problem will soon be found.
Do not store plastic (or other) dolls in plastic bags. Also keep them away from mothballs and insecticides. Factors contributing to the onset of the breakdown may be storage in an acidic environment (perhaps from a manufacturing or processing flaw, from packaging materials or air pollution) or hydrolysis, as a result of a humid storage environment.
(Thanks to the Australian Archives for information on the problem which they are trying to solve.)
Our thanks to our member, Barbara Hancock, for this article.