416 



CHEMISTRY. 



[VEGETABLE ALKALIES, ETC. 



from the intensely powerful effecU they hare on the 

 annual system. And we ihould strongly urgo on our 

 readers the prudenoe of being content with their brief 

 description, rather than to attempt their production. 



Salicyl, to which we now direct attention, U olit 

 friu a product of vegetable life, aalicin, and derives it* 

 name front the willow tree, in the bark of which it may 

 b found. The crystal* of aalicin have a beautifully 

 silken appearance. It U prepared by infusing the bark 

 of the willow, poplar, <tc-, in hot water, and heating with 

 the protoxide of lead. Hydroeulphuric acid* is then to 

 be passed through the solution, to remove the lead as 

 sulphide. Salicyl is the base of this substance. 



There are other compounds analogous to ethyl, <tc , 

 which we shall omit to noUce altogether, or refer to them 

 in a more ooavenient place. 



lu the perusal of this chapter, our readers will have 

 perceived that we have entered into a novel branch of 

 organic chemistry, in which wo find fresh analogies, and 

 a very interesting series of compounds. As we may havo 



rin to refer to the substances we have described, we 

 11, for the present, end our remarks by presenting the 

 symbols of the constitution of each, in a tubular form, so 

 as to be convenient for future reference ; and shall then 

 proceed to give a description of the alkaloids and vege- 

 table acids. 



Table ihotcing the conititution of Ethyl, Methyl, Amyl, Beraoyl, and tome of their Compounds. 



CHAPTER IX. 

 VEGETABLE ALKALIES OB ALKALOIDS, AND ACIDS. 



Iir our last chapter we included a description of salicyl, 

 because its analogies are in accordance with those of 

 ethyl, ic. Salicin, which contains it, would appear to 

 belong to the alkaloids. We have accordingly chosen it 

 as the hut of the basic series, before commencing an 

 account of the vegeto-alkalies. 



These substances differ materially from all other or- 

 ganic matters with which we have yet been engaged, in 

 the fact of their containing nitrogen as an element of 

 r composition. They are, generally speaking, prin- 

 ciples existing in minute quantities in the plants from, 

 which they are obtained. They are but slightly soluble 

 in water, their proper menstrum of solution being alco- 

 hol With acids they act as bases, and in their specific 

 character resemble the alkalies ; hence they have received 

 the title of alkaloids. Some of them are extremely 

 poisonous, whilst others exert a highly beneficial innu- 

 ence on the human system. After giving a general 

 description of the alkaloids, we shall proceed to describe 

 tome of the leading vegetable acids. 



STRYCHNINE. This alkaloid is obtained from the nvx 

 tomita, which also contains another substance called 

 BBUCIM : in fact, these two alkaloids are often mistaken | 

 for each other, in unskilful hands. Strychnine, in the 

 pure state, has a crystalline form, an intensely bitter 

 taito, U barely soluble in water, but dissolves easily in 

 ng spirits of wine. Bnicine may bo separated from 

 strychnine by its solubility in cold alcohol. It ia also 

 more soluble by far, in water, than strychnine. 



A sulphate of strychnine U readily produced, as is the 

 acetate, by the action of the corresponding acids on the al- 

 kaloid. Urn, -i no forms analogous salts with the same acids. 

 T late years, strychnine, or, as it is often callc.l, 

 strychnia, has obtained a painful notoriety in connection 

 with oases of poisoning ; more especially in that of the 



SM <, p. S7. 



celebrated Palmer's case. It is, perhaps, the most dread- 

 ful poison which can be administered to a human being. 

 In quantities of a fraction of a grain to one grain, ac- 

 cording to the constitution of the victim, its effects 

 are fatal. Rigid contortions of the muscles of the body 

 are its symptoms of poisoning. The sufferer retains 

 his mental powers undiminished, although he is racked 

 with pain ; and, at last, he is put out of misery by con- 

 vulsions, which are truly horrible to behold. 



The tests for the presence of strychnine are twofold 

 chemical and physiological ; the latter having been first 

 introduced to notice by the late lamented Dr. Marshall 

 Hall. 



If a grain of strychnine be placed on a plate with a 

 little powdered bichromate of potass near it, and a drop 

 of concentrated sulphuric acid be let fall between them, 

 a rich purple colour is instantly produced when all i 

 are stirred together, but which speedily changes to a red 

 tint, which is pennanent. The same colour is produced 

 by using the red ferri-cyanide of potass in place of the 

 bi-chromate. 



The physiological test is more satisfactory, and may 

 be illustrated as follows: Dissolve |th of a grain of the 

 acetate of strychnine in a little boiling alcohol, and add 

 thereto two ounces of cold water. Place in the solution 

 two small frogs. For some time no effect will be ap- 

 parent. This U best conducted in a tall glass jar, the 

 top of which should be covered, for reasons which will 

 be presently seen. 



After a time the poison will bo absorbed into the sys- 

 tem of the animals. If the glass which contains them be 

 then shaken, the poor creatures will instantly sull'i-r ficm 

 convulsions stretching out each limb, which will become 

 rigid ; they will utter piercing shrieks, and show all the 

 usual effects of strychnine poisoning. After a time the 

 eyeballs will swell, and death ends their sufferings. 





