THE INFLUENCE OF CHEMICAL FACTORS 69 



stage of the intoxication convulsions are the most prominent symptom, 

 but even during these the oxygen absorption is diminished and may 

 be less than half the exchange during normal rest. When the toxic 

 symptoms begin to disappear the animal is usually paralysed, but at 

 this stage the oxygen absorption is increased as compared with that 

 during the convulsions and may be increased above the normal. 

 Geppert determined the oxygen content of the arterial and venous 

 blood during intoxication with potassium cyanide and found the arterial 

 to be normal while the venous contained, as one would expect from the 

 colour, much more oxygen than usually. Potassium cyanide has no 

 effect on the combination of haemoglobin with oxygen, and the only 

 possible explanation of the facts observed is that the power of the 

 tissues to utilize oxygen is diminished. The poison appears to affect 

 all tissues in like manner. Loeb and Wasteneys [1913, 1,2] have 

 observed that hydrogen cyanide inhibits also the oxidations in fish 

 embryos and in medusae (Gonionemus}. 



A detailed study of the mechanism of the action of prussic acid has 

 not been attempted since Geppert's excellent work was published. 

 It is not known whether it is the oxidation stage alone of the catabol- 

 ism which is inhibited or if preliminary stages are also or perhaps 

 exclusively affected. The results obtained by Loewy, Wolff and 

 Osterberg [1908] concerning the effect of prussic acid on protein 

 metabolism would seem to point towards the latter alternative. It 

 is obvious that a search for intermediate catabolites produced during 

 intoxication with prussic acid ought to be made, and the possible 

 effect of the poison on anoxybiotic organisms should also be studied. 

 Geppert mentions as a chemical analogy to the action of prussic acid 

 on living tissues that traces of prussic acid inhibit the oxidation of 

 formic acid by iodic acid. 



Phosphorus. A similar though much less pronounced effect than 

 that of prussic acid on the metabolism is shown by phosphorus, accord- 

 ing to experiments by Bauer [1871] on dogs, Scheider [1895] n 

 rabbits, and Welsch [1905] on dogs and rabbits. The action of phos- 

 phorus is chronic and cumulative while that of prussic acid develops 

 and disappears in a very short time. 



!.() Lipoid-soluble non-specific substances or narcotics do not 

 appear to have any influence upon the oxidative processes of higher 

 animals in concentrations which are sufficient to bring about narcosis. 

 This result, though seemingly in contradiction to that mentioned above 

 for single cells, is really in good agreement with it, since the concentra- 



