July 13, 1888.] 



SCIENTIFIC NEWS. 



45 



as they extinguish a burning taper. Yet nitrogen is not 

 a poison, whilst carbonic acid is. 



Nitrogen simply destroys life by blocking out oxygen. 

 Given the presence of 20 per cent, of oxygen, the 80 per 

 cent, of nitrogen possesses no toxic effect. 



The carbonic acid, on the contrary, is specifically toxic. 

 The admixture of 20 per cent, or of 80 per cent, of oxygen 

 does not materially alter the case. Oxygen or no oxygen, 

 C0 2 is a poison. 



(B) Consider next, What a poison is. 



It is an agent capable of destroying life. 



The use of the phrase deadly poison is surplusage. If 

 a body be a poison, it is deadly ; if it be not deadly, it is 

 not a poison. 



My definition limits the mechanism whereby the toxic 

 effect is induced, to chemical and physiological actions. I 

 am conscious that this definition suggests classification. 

 Certain it is, that Nature hates classification as truly as 

 she declines definitions. 



Let us trace some of these mechanisms of toxic activity. 

 I select three illustrations of poisons belonging to different 

 classes. 



(1) Sulphuric Acid. — If a person swallows sulphuric 

 acid, the tissues with which the acid comes into contact 

 are more or less charred — " more or less," that is, ac- 

 cording to the strength of the acid and the time of contact. 



Charred. — This implies a chemical act, dependent on 

 the power of sulphuric acid to combine with water. 



The portion of the body thus charred dies. We call 

 this molecular death. (This does not imply that the per- 

 son is dead. Health is disturbed. Health is derived 

 from the old Saxon word " Wholth," signifying entirety. 

 Health implies the perfect rhythmicity of the bodily 

 functions. It is that condition expressed with charming 

 simplicity by Suffolk folk, who describe being " quite 

 well " by the phrase " they feel all over alike." The 

 charring process [molecular death] has disturbed rhyth- 

 micity.) Before long all the members suffer with the 

 charred stomach. The death, localised in the first in- 

 stance, becomes general, the death of the entire body, 

 i.e., of the person, eventually taking place. We call that 

 somatic death. This is poisoning by sulphuric acid. 

 But the primary act of disturbance — the first interference 

 with the rhythmicity of health — resulted from the chemi- 

 cal power of sulphuric acid to combine with water. It 

 will be evident that the chemical action of a poison de- 

 pends on the chemical relationships of that poison. 



(2) Carbonic Oxide. — Carbonic oxide is a true poison. 

 It is a gas that may often be seen burning with a blue 

 flame on the top of a bright fire in the open fire-stove. 



Its importance amongst poisonous bodies depends on 

 the circumstance that it is evolved in many manufacturing 

 operations (e.g., lime and brick kilns, iron blast furnaces, 

 copper-refining furnaces, etc.), and that it is always pre- 

 sent in small quantity in coal-gas, constituting its true 

 toxic constituent. 



What, then, is the mechanism whereby carbonic oxide 

 destroys life ? The active agent of the blood is its red 

 colouring matter (Hamioglobin). To the chemist this 

 substance abounds in wonder. 



We have reason to believe that haemoglobin is formed 

 from the albumenoids, the synthesis of which albumen- 

 oids is limited to the vegetable. Essential as the albu- 

 menoids are to animal life, the animal is dependent for 

 their formation on the synthetical processes taking place 

 in the plant laboratory. The animal, however, can 

 transmute one albumenoid into another (e.g. he can 



change albumen into a peptone), whilst he can also form 

 from them bodies of less complicated constitution (e.g., 

 fat) — in other words, he can lower them in the scale. 

 But, save with one exception, he cannot use them to effect 

 higher synthetical formations. This single exception is 

 haemoglobin. 



It is no matter for surprise that a body like haemo- 

 globin — one of the chief actors, so to speak, in the curious 

 drama of life and living, which comes on the scene 

 through a stage opening of which we neither know 

 construction nor whereabouts — should possess unique 

 chemical properties and relationships. I shall only 

 trouble you this evening with one of these relationships. 



As a general rule a substance that combines with 

 oxygen with difficulty parts from it with ease, and vice 

 vena. It is difficult to make gold combine with oxygen, 

 but it is easy to decompose oxide of gold. Potassium 

 easily combines with oxygen, but it required the genius 

 of a Davy and the resources of the Royal Institution to 

 separate potassium and oxygen. 



In haemoglobin, however, we have a substance that 

 combines with, and delivers up, its oxygen (i.e., is 

 oxidised and reduced) with almost equal facility under 

 similar conditions. Upon this and other chemical 

 characteristics of haemoglobin — as the oxygen-receiver, 

 the oxygen-carrier, the oxygen-deliverer, the carbonic- 

 acid receiver, carrier, and deliverer — the act of living 

 depends. In other words, life depends on the integrity 

 of the haemoglobin — on the rhythmicity of those 

 chemical processes in affecting which haemoglobin is the 

 primary worker. 



With these facts before us, let us turn to the toxic 

 action of carbonic oxide. 



The haemoglobin at once seizes upon and combines 

 with the carbonic oxide, carbonic-oxide-haemoglobin being 

 formed. 



Two difficulties arise : 



r. The haemoglobin, saturated with carbonic oxide, 

 cannot combine with oxygen. Regarding haemoglobin as 

 a common carrier, the carriage is full. 



2. The haemoglobin, being saturated with carbonic 

 oxide, cannot get rid of the carbonic oxide under the 

 ordinary conditions of respiration and circulation. Again, 

 regarding the haemoglobin as a common carrier, the 

 vehicle, full up, cannot be unloaded. 



To put all this in scientific phraseology, carbonic-oxide- 

 haemoglobin is a comparatively stable compound, being 

 neither decomposed by the presence of an excess of 

 oxygen (as in the lungs) nor by carbonic acid. What 

 must happen ? The man dies because the integrity of 

 the haemoglobin has been disturbed — because the normal 

 sequence of its oxidation and reduction has been inter- 

 rupted by the formation of carbonic oxide haemoglobin. 



We call the result of all these chemical actions and 

 interferences, poisoning by carbonic oxide. 



3. Strychnine (the poison derived from St. Ignatius' 

 Bean). 



How does strychnine act ? We know sadly little 

 about it — so little that we use the phrase "physiolo- 

 gical action " to express our want of knowledge. But we 

 know something. 



A marked chemical characteristic of strychnine is its 

 power to combine with oxygen when the oxygen is pre- 

 sented to it in a nascent form. 



Note then the conditions. Strychnine is in the body. 

 There is also present in the blood haemoglobin loosely 

 combined with oxygen, which oxygen the haemoglobin is 



