regard to morphology and anatomy into one separate group, so 

 the latter observes that the individuals of such a gi'oup resemble 

 each other by containing certain widely-distributed substances in 

 exceedingly large quantities (for instance, tannic acid, starch), or 

 by yielding certain compounds of peculiar character in regard to 

 smell, taste or effect on the animal organism, substances which are 

 either confined to one family or only present in but few others. 

 Of such substances, which appear to link together different 

 families, each group contains either one or more, and amongst 

 them are of high consequence the alkaloids. The number of 

 orders or siiborders of plants amounts to about 400 ; when we admit 

 that on the average each of them contains two or three specific 

 alkaloids, it follows that the whole vegetable kingdom produces 

 about 1000, of which I need scarcely say only the minor portion 

 (about one-fifth) has become accurately known. In making this 

 computation, it has not been left out of regard, that some of the 

 vegetable families (Labiatse, Compositse) are at least largely free 

 of alkaloids, that some have only one in common (for instance. 

 Berberin belongs, as far as our knowledge goes, alike to 

 Anonacese, Berberidese, Cassiese, Menispermese, Papaveracese, 

 Banunculacese, Butacese), and that some families contain more 

 than two or three alkaloids (Cinchonesej Papaveracese, 

 Solanacese, &c.). 



Whereas the presence of an essential oil in vegetables is imme- 

 diately recognised by the smell, general indications for the pre- 

 sence of alkaloids are wanting. Indeed, all the alkaloids known 

 at present possess a very perceptible taste, which is mostly bitter and 

 acrid, both to the highest degree; and those among them that are 

 volatile have also a specific odour; but these characteristics of 

 taste and smell are shared by many other substances devoid of 

 alkaloid properties. On the other hand, it would be unwarrant- 

 able to conclude fi'om little or no taste the absence of alkaloids in 

 a plant, as the alkaloid, when only present in minute quantities, 

 may not be detected by means of tasting. In this case, the 

 isolation of the alkaloid is often surrounded by the greatest 

 difficulties. 



Before examining any vegetables on alkaloids, it must be decided 

 first, if the latter are volatile or not. When a herb is endowed 

 with a strong smell, that becomes more striking by adding a solution 

 of caustic potash, the presence of a volatile alkaloid is evident. 

 The non-volatile alkaloids are not so easily found out, since they 

 may not be recognised by the taste; consequently, an alkaloid, 

 before it can be considered as such, must be isolated in almost a 

 pure form. Their estimation and isolation become therefore 

 simultaneously necessary. Tliis process of isolation serves, at the 

 same time, for determining the quantity. 



