20 POISONS : THEIR EFFECTS AND DETECTION. [§ 17 . 
annihilation of organs, or destruction of their functions, injure health, 
or, under certain conditions, destroy life.” Robert says :—“ Poisons are 
organic or inorganic unorganised substances originating in the organism 
itself, or introduced into the organism, either artificially prepared, or 
ready formed in nature, which through their chemical properties, 
under certain conditions, so influence the organs of living beings, 
that the health of these beings is seriously influenced temporarily or 
permanently.” 
In the first edition of this work an attempt was made to define a 
poison : the definition slightly abbreviated is thus :— A substance may 
be called a poison if it is capable of being taken into any living 
organism, and causes, by its own inherent chemical nature, impairment 
or destruction of function. We prefer this definition to Robert’s, and 
believe that it fairly agrees with what we know of poisons. 
II.—Classification of Poisons. 
§ 17. At some future time, with a more intimate knowledge of the 
way in which each poison acts upon the various forms of animal and 
vegetable life, it may be possible to give a truly scientific and philoso¬ 
phical classification of poisons—one based neither upon symptoms, upon 
local effects, nor upon chemical structure, but upon a collation and com¬ 
parison of all the properties of a poison, whether chemical, physical, or 
physiological. No perfect systematic arrangement is at present attain¬ 
able : we are either compelled to omit all classification, or else to arrange 
poisons with a view to practical utility merely. 
From the latter point of view, an arrangement simply according to 
the most prominent symptoms is a good one, and, without doubt, an 
assistance to the medical man summoned in haste to a case of real or 
suspected poisoning. Indeed, under such circumstances, a scheme some¬ 
what similar to the following probably occurs to everyone versed in 
toxicology :— * 
A. Poisons causing Death immediately, or in a few Minutes. 
There are but few poisons which destroy life in a few minutes. 
Omitting the strong mineral acids, carbon monoxide, carbon dioxide, 
with the irrespirable gases— Prussic acid, the cyanides, oxalic acid, and 
occasionally strychnine, are the chief poisons coming under this head. 
B. Irritant Poisons (symptoms mainly pain, vomiting, and purging). 
Arsenic, antimony, phosphorus, cantharides, savin, ergot, digitalis, 
colchicum, zinc, mercury, lead, copper, silver, iron, baryta, chrome, yew, 
laburnum, and putrid animal substances. 
