50 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



NICOTINE : ITS USE AND VALUE IN HORTICULTURE. 



By Geo. Edw. Williams. 



[Lecture delivered February 25, 1902.] 



Nicotine is an alkaloid which occurs in various parts of the Tobacco 

 plant. The compound owes its name to one Jean Nicot, a Frenchman, 

 who first introduced the seeds of the Tobacco plant into France in the year 

 1560. Nicotine when pure is a colourless compound of an oily nature, 

 but readily soluble in water. It has rather a sickly smell, not at all like 

 the odour we usually associate with Tobacco. It acts upon all animal life 

 as an extremely powerful poison ; it is the strongest insecticide known to 

 the scientific world that can be used with safety in checking the ravages 

 of blight and other insects that are injurious to vegetable life. It has a 

 very high boiling point, and great care has to be exercised in extracting it 

 from the Tobacco plant, as it is very easily oxidised. 



Of course in the wide range of chemistry other compounds have been 

 found that are strong insecticides ; for example, the well-known carbolic 

 acid is a very strong disinfectant and insecticide, but it also acts as 

 a poison to vegetable life. Then we have substances of sulphate of 

 copper and weak solutions of mineral acids, all of them splendid insecti- 

 cides, but at the same time they check and in many cases stop vegetable life. 

 They are, however, useful as fungicides. Quassia liquid, again, in some 

 cases acts as a good insecticide, but is not sufficiently powerful to kill 

 many kinds of blight and parasitic diseases common to plant life. 



In studying the chemistry of insecticides and their relation to plant 

 life one is bound to come to the conclusion that nicotine is the compound 

 amongst all others that can be used by the horticulturist with perfect 

 confidence and success. It is absolutely harmless to all forms of vege- 

 table life if used under proper conditions. I am obliged to put in that 

 saving clause because some people are much inclined to take advantage of 

 broad general statements. Still, though I say " nicotine is harmless to 

 vegetable life," no one, I imagine, would be so insane as to syringe 

 his Rose trees with pure nicotine. Oxygen is not only harmless but 

 essential to all animal life ; yet it would be madness for us to breathe 

 nothing but pure oxygen all day and every day, and if we did we should 

 certainly not breathe very long. No, we must breathe oxygen under 

 proper conditions, and then it sustains our life. So with the use of 

 nicotine as an insecticide; it must be used under proper conditions ; and if 

 used under these conditions it will not injure or impair vegetable life, but 

 will prolong and strengthen it. 



Not only by practical experiment upon various forms of plant life do 

 we find that nicotine is harmless, but by experiments upon forms of life 

 just one step higher than vegetable life, viz. microbes. A microbe is a small 

 bit of life, and is by nature more or less vegeto- animal. It is neither an 

 animal as we ordinarily understand the word, nor is it a vegetable as we 



