CHAPTER XI. 



MISCELLANEOUS. 



In this chapter a description will be given of various sub- 

 stances used on the farm which do not come under the category 

 of the materials discussed in the preceding chapters. 



The subjects to be dealt with are numerous and diverse, so 

 that no attempt can be made to attain any continuity or 

 logical order. 



For convenience we may consider in turn the chemical 

 nature of the substances used as 



I. Disinfectants and antiseptics ; 

 II. Fungicides ; 



III. Insecticides; 



IV. Plant poisons ; and, lastly, those used for 

 V. Other purposes. 



I. Disinfectants and Antiseptics.— A real disinfectant 



is a substance which destroys the micro-organisms (and their 

 spores) which give rise to putrefaction, disease, or other chemical 

 changes. An antiseptic is a body which prevents their growth, 

 bilt may or may not destroy them. All disinfectants are thus 

 antiseptics, but all antiseptics are not disinfectants. 



A great many substances act as disinfectants in strong solu- 

 tion, but obviously only those which by their presence in 

 relatively small quantity act destructively on micro-organisms 

 are worthy^f consideration under this heading. 



Powerful disinfectants are found among chemical compounds 

 of very different types, and no perfectly satisfactory method 



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