other ectoparisites are killed by baths of 5 per cent, potassium permanganate, or a light brown solution of ligno-sulphite and ulcerated wounds are touched with a brush, or wad, soaked with concentrated ligno-sulphite.
In the first museums of natural history abnormalities were collected, but later such specimens were discredited as of no value in the system of biological classification and seldom of interest in phylogeny. However, in recent years developmental mechanics has fixed our attention upon the causes of development and by means of the experimental methods many kinds of malformations have been created at will. We now seek the explanation of abnormalities occurring in nature, produced
by "nature experiments," and these monsters and variations again become of value as museum specimens. The results of experimentation carried on in the institution are preserved and exhibited in the museum (Fig. 17), in the form of preparations, photographs and wall charts, and in addition preparations from other experimenters and malformations from nature are being collected. Regarded as of primary importance are the results of experiments concerned with development, regeneration, adaptation, variation in instincts, heredity and species transformation in animals and plants. Of secondary importance are the abnormalities of form and color like supernumerary structures, albino or nigrescent individuals, which have not been produced experimentally, and whose cause is unknown, or at most can only