it ceased to be the efficient oxygen carrier of normal _hæmoglobin_.
This interference with the ordinary action of _hæmoglobin_ constituted
poisoning by carbonic oxide. In connection with this subject the
lecturer referred to the use of the spectroscope as an analytical
agent, and showed the audience the spectrum of blood extracted from
the hat of the late Mr. Briggs (for the murder of whom Muller was
executed), and this was the first case in which the spectroscopic
appearances of blood formed the subject matter of evidence. The third
illustration of poisoning was poisoning by strychnine. Here again the
power of the drug for undergoing oxidation was illustrated. It was
noted that although our knowledge of the precise _modus operandi_ of
the poison was imperfect, nevertheless that the coincidence of the
first fit in the animal after its exhibition with the formation of
reduced _hæmoglobin_ in the body was important.

There followed upon this view of the chemical action of poison in the
living body this question: Given a knowledge of certain properties of
the elements--for example, their atomic weights, their relative
position according to the periodic law, their spectroscopic character,
and so forth--or given a knowledge of the molecular constitution,
together with the general physical and chemical properties of
compounds--in other words, given such knowledge of the element or
compound as may be learned in a laboratory--does such knowledge afford
us any clew whereby to predicate the probable action of the element or
of the compound respectively on the living body? The researches of
Blake, Rabuteau, Richet, Bouchardat, Fraser, and Crum-Brown were
discussed, the results of their observations being that at present we
were unable to determine toxicity or physiological action by any
general chemical or physical researches. The lecturer pointed out that
such relationship was scarcely to be expected. Poisons acted on