POISONOUS ALKALOIDS AND ALBUMINOIDS. 



359 



during putrefactive processes are non-poisonous, whilst others 

 formed during the same process may be extremely toxic ; a 

 considerable number of the non-poisonous forms especially 

 have been manufactured synthetically or by analysis ; tri- 

 methylamine and dimethylamine, for example, both of which 

 as well as Pentamethyline diamine (Cadaverine) may be 

 obtained as putrefactive products and may also be prepared 

 synthetically by the chemist, the artificial Cadaverine in 

 sufficiently large doses giving rise to all the symptoms 

 and post-mortem appearances of an attack of cholera. 

 Of the poisonous kinds a substance known as betaine, 

 which is closely related to nicotine and glycocol, has been 

 found in both vegetable alkaloids, and in the human urine, 

 in the latter being apparently the result of decomposition 

 changes going on in the alimentary canal under the action of 

 bacteria. It is one of the substances formed during the 

 processes of decomposition of albuminoid bodies ; it also has 

 been prepared in the laboratory. 



The formulae of a number of these substances is exceedingly compli- 

 cated, but they all appear to be allied to or even to be derived from what 

 is known as the pyridine base, a non-saturated alkaloid, derived from 

 the products of dry distillation of bone or wood, from the ammoniacal 

 liquor of coal distillates, and 

 from the action of heat or 

 strong alkalies on the vegetable 

 alkaloids. Its composition will 

 be best understood by reference 

 to the diagram given by Pictet 

 (Fig. i). It is very nearly re- 

 lated to benzol ; the only dif- HC -CH 



ference being that one of the 

 CH groups is replaced by N. 

 Thus benzol has a formula 

 (Fig. 2). Neither of these 

 substances has all the carbon 



bonds satisfied, so that each HC- _ CH 



C and the N having a bond 



free (those drawn within the 



hexagon) to combine with 



other atoms, or groups of 



atoms, there may be enormous N 



numbers of derivative or addi- FIG i. 



tion and substitution products formed ; for instance, all the bonds free in 



pyridine may be saturated by the addition of a single atom of hydrogen to 



each, when we have what is known as the piperidine alkaloid (Fig. 3), and 



by adding one, two or three ethyl or methyl groups to the free bonds in 



place of one, two, or three of the H's we may obtain methyl piperidine, 



