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THE POPULAR SCIENCE MONTHLY 



other ectoparisites are killed by baths of 5 per cent, potassium perman- 

 ganate, 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. How- 

 ever, 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, pro- 



FiG. 18. 



duced by " nature experiments," and these monsters and variations 

 again become of value as museum specimens. The results of experi- 

 mentation 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 pri- 

 mary importance are the results of experiments concerned with devel- 

 opment, regeneration, adaptation, variation in instincts, heredity and 

 species transformation in animals and plants. Of secondary im- 

 portance are the abnormalities of form and color like supernumerary 

 structures, albino or nigrescent individuals, which have not been pro- 

 duced experimentally, and whose cause is unknown, or at most can only 



