44 



SCIENTIFIC NEWS. 



[July l 3l IS 



POISONS AND POISONING. 



A Lecture delivered by C. Meymott Tidy, Esq., 

 M.B., etc., before the Royal Institution of 

 Great Britain. 



TOXICOLOGY is the science of "poisons and poison- 

 ing." How comes " toxicology " to mean " the 

 science of poisons ? " The Greek word -t6%ov (derived 

 perhaps from Tv^^avui) signified primarily that specially 

 Oriental weapon which we call " a bow." In the very 

 earliest authors, however, it included within its meaning 

 " the arrow shot from the bow." 



In the first century, a.d., in the reign of Nero (a 

 poisoner and a cremationist), Dioscorides, a Greek writer 

 on Materia Medica, uses the expression to to^ikov to 

 signify " the poison for smearing arrows with." Thus, 

 by giving an enlarged sense to the word — for words ever 

 strive to keep pace, if possible, with a scientific progress 

 — we get our modern and significant expression "Toxic- 

 ology," the science of poisons and poisoning. 



And there, in that little piece of philology (to^ov and 

 TofiKoV — a bow and a poison), you have not only the 

 derivation of the word, but the early history of my 

 subject. 



A certain grim historical interest gathers around the 

 story of poisons and poisoning. It is a history worth 

 studying, for poisons have played their part in history. 

 The " subtil serpent " taught men the power of a 

 poisoned fang. History presents poison in its first 

 aspect in a far less repulsive form than it has assumed 

 in latter days — for a world may grow wiser and 

 wickeder withal. Poison was in the first instance a 

 simple instrument of " open warfare." For this purpose 

 our savage ancestors tipped their arrows with poison, in 

 order that they might inflict certain death on a hostile 

 foe. It can scarcely be questioned that the poison of the 

 snake was the first material employed for this object. 

 The use of vegetable extracts (such as curarine, the active 

 principle of which is str} chnine, and is employed at the 

 present time by certain uncivilised communities) belongs 

 to a later period. 



And so the first use of poison was for an "open fight." 

 It was reserved for later times to mix the cup of kinship 

 with a treacherous, diabolical venom ! 



" An open fight ! " Is the suggestion (think you) too 

 wild, supposing "war chemists," with their powders, 

 their gun-cotton, and their explosives never to have 

 been invented, that nations would have turned for their 

 " instmmenta belli" to toxicologists and their poisons. 

 I claim, however (notwithstanding that in this we missed 

 our chance), no more for my subject than its due, if I 

 attempt to localise the very cradle-room of science as the 

 laboratory of the toxicological worker. 



Besides snake-poison, the use of animal fluids, either 

 alone or mixed with snake-poison, with which to charge 

 arrows, is pre-historic. Thus in old Greek legend we 

 read how Hercules dipped his arrows in the gall of the 

 Lernoean hydra to render the wounds they inflicted 

 incurable and mortal, and how at last Hercules himself 

 was poisoned by his wife's present, the tunic of the 

 Centaur Nessus stained with his poisonous blood, which 

 she vainly hoped might restore her husband's affection, 

 but which only procured for him the frightful agonies 

 and tortures of which he died. 



The use of putrid blood as a poisonous agent, and the 

 admixture of the snake-poison with blood, constitutes a 

 curious history, when regarded in connection with our | 



present views on septicaemia. The toxic activity of 

 putrid animal fluids seems to have been recognised in 

 very early times. And I suppose these early observa- 

 tions on the effects of putrid blood explain the view 

 almost universally adopted, that blood itself was a 

 poison. Thus the deaths of Psammenitus, King of 

 Egypt (as recorded by Herodotus), and of Themistocles 

 (as recorded by Plutarch), were said to have been effected 

 by the administration of bullock's blood. Even Blumen- 

 bach, so lately as the middle of the last century, per- 

 suaded one of his class (by way of settling the question) 

 to drink seven ounces of warm bullock's blood. The 

 young man (good as were his intentions) did not die a 

 martyr to science. 



The history of poisons and poisoning, the contents of 

 the first chapter of which I have thus briefly indicated 

 (viz., the toxicity of the snake-poison and of blood), 

 down to the final chapter, which commences with the 

 properties and reactions of arsenic, forms a tempting 

 subject for my lecture to-night. The histories of Circe 

 and Medea — of Livia Drusilla and Locusta — of Tiberius 

 and Nero — of the Borgias — of Hieronyma Spara, Tofana, 

 Catherine de Medicis, St. Croix, and a host of other 

 worthies, have proved charming topics for the marvel- 

 monger. And it would not have been an unworthy 

 subject to bare the truths underlying the stories of 

 generations of story-tellers, obscured as they have be- 

 come by the demand of ignorant sensationalism and the 

 terrors of a mean superstition. But this is not the 

 subject I have proposed to myself for the discourse to- 

 night. 



" What is a Poison ? " 



Two difficulties present themselves in answering this 

 question : — 



i. The law has not defined a poison, notwithstanding 

 that the law at times demands of science the definition of 

 a poison. 



I know a case, for example, where a prisoner, indicted 

 for the administration of a poison, escaped because the 

 scientific witness declined to say that the drug adminis- 

 tered by the prisoner was a poison. 



2. The popular definition of a poison is far from being 

 a sound, much less a scientific definition. Generally 

 speaking, it comes to this, that " A poison is a drug that 

 kills rapidly when administered in a small quantity." 



The phrase " a small quantity " as regards weight, and 

 the word " rapidly " as regards time, are as indefinite as 

 the classical piece of chalk as regards size. 



I define a poison as — 



" Any substance which otherwise than by the agency 

 of heat or electricity is capable of destroying life either 

 by chemical action on the tissues of the living body, or 

 by physiological action after absorption into the living 

 system." 



(A) It will be convenient to consider first, What a 

 poison is not. 



It is not an agent that destroys life by physical influ- 

 ences, such as heat and electricity. 



It is not an agent that destroys life by any purely 

 mechanical act (e.g., pins are not poison, although fairly 

 included in the phrase "destructive things"). 



It is not an agent that destroys life by the mere block- 

 ing out of that which is necessary to maintain life (i.e., 

 the action of a substance to be a poison must be more 

 than mechanical). 



This latter point requires further consideration : — 



Both nitrogen and carbonic acid destroy life as certainly 



