[29] “Celui qui aura occasionné à autrui une maladie ou incapacité de travail personnel en lui administrant volontairement, de quelque manière que ce soit, des substances qui, sans être de nature à donner la mort, sont nuisibles à la santé.”--Art. 317, _Penal Code_. § 16. =Scientific Definition of a Poison.=--A true scientific definition of a poison must exclude all those substances which act mechanically,--the physical influences of heat, light, and electricity; and parasitic diseases, whether caused by the growth of fungus, or the invasion of an organism by animal parasites, as, for example, “trichinosis,” which are not, so far as we know, associated with any poisonous product excreted by the parasite;--on the other hand, it is now recognised that pathogenic micro-organisms develop poisons, and the symptoms of all true infections are but the effects of “toxines.” The definition of poison, in a scientific sense, should be broad enough to comprehend not only the human race, but the dual world of life, both animal and vegetable. Husemann and Kobert are almost the only writers on poisons who have attempted, with more or less success, to define poison by a generalisation, keeping in view the exclusion of the matters enumerated. Husemann says--“We define poisons as such inorganic, or organic substances as are in part capable of artificial preparation, in part existing, ready-formed, in the animal or vegetable kingdom, which, without being able to reproduce themselves, through the chemical nature of their molecules under certain conditions, change in the healthy organism the form and general relationship of the organic parts, and, through annihilation of organs, or destruction of their functions, injure health, or, under certain conditions, destroy life.” Kobert 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 I made an attempt to define a poison thus:--_A substance of definite chemical composition, whether mineral or organic, 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_. I prefer this definition to Kobert’s, and believe that it fairly agrees with what we know of poisons. II.--Classification of Poisons.