NICOTINE : ITS USE AND VALUE IN HORTICULTURE. 



51 



generally use the term, but it is half-and-half, somewhere between the 

 two. A microbe is a peculiar sort of gentleman, a gentleman rather diffi- 

 cult to deal with, as the small-pox is showing us just now. Microbes are 

 neither " flesh, fowl, nor good red herring." Vegetable life predominates 

 in all microbes rather than animal vitality, and they are more closely 

 related to the homely Cabbage plant than they are to the still more 

 homely flea. Now by direct and careful experiment we find that nicotine 

 has no appreciably injurious effect upon the growth of microbes. Many 

 wonderful discoveries have been made in bacteriology within recent years. 

 Microbes which cause or are found to be connected with certain diseases 

 have been discovered, classified, and examined under the microscope, and 

 celebrated bacteriologists have become so expert in the science that they 

 can immediately say whether a group of microbes are those of typhoid 

 fever, cholera, anthrax, scarlet fever, &c. 



The following experiments have been carried out to ascertain whether 

 nicotine acted as a disinfectant as well as an insecticide. The microbes 

 of certain diseases such as typhoid fever, anthrax, and cholera were 

 enclosed in sealed jars, and the vapour of pure nicotine was passed 

 through the jars for a period of forty-eight hours. At the end of that 

 time, after microscopic examination, the various microbes were found to 

 be alive and capable of reproduction, nicotine having no appreciable effect 

 upon these organisms. This is rather conclusive evidence against per- 

 mitting smoking inside stage carriages during the prevalence of small-pox 

 on the plea that it would keep off infection. 



By direct experiment again we find that the vapour of nicotine will 

 not injure the natural bloom on delicate fruit ; it will not affect the scent 

 of choice flowers, and so far as plant life is concerned it does not either 

 injure or retard growth. Thus by experiment it has been conclusively 

 proved that nicotine is harmless to vegeto-animal life and all organic life 

 below this order. 



There is one other interesting lesson that may be learnt from the 

 previously mentioned experiments, which is this. All compounds that 

 are good disinfectants are not necessarily suitable materials to be used 

 as insecticides in horticulture ; and vice versa all compounds that are 

 suitable for use as insecticides in horticulture are not necessarily suitable 

 as disinfectants. If this fact is borne in mind it will prevent a tremen- 

 dous amount of damage being done by people who profess to understand 

 the chemistry of insecticides which may be used on plant life, but who 

 unfortunately have not even got as far as the experimental stage in 

 these matters. 



We must now therefore definitely state that the proper use of nicotine 

 in horticulture is extremely valuable as an insecticide of the first order, 

 and one which is reliable, efficient, and harmless to all forms of vegetable 

 life. 



There are three ways of using the compound. 



First, by the application of heat, and so vaporising the nicotine, and 

 bringing the vapour into contact with the plant or plants requiring 

 treatment. 



Second, by direct application in a liquid form to the plant. 

 Third, by mixing the nicotine with a combustible fibrous medium 



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