320 CATALYST POISONS AND NARCOTICS CHAP. 12 



adaptation in somewhat larger quantities, and reduction of the quantum 

 yield of photoreduction with hydrogen by a factor of 1/2 (c/. p. 314). 



Green, McCarthy, and King (1939) investigated the effect on the 

 metabolism of Chlorella of poisons which are known to affect specifi- 

 cally the catalytic activity of enzymes containing copper, e. g., thiourea, 

 allylthiourea, 8-hydroxyquinoline and sodium diethyl dithiocarbamate, and 

 found that all of them inhibit both photosynthesis and respiration of 

 this organism. 



B. Narcotics* 



It was stated on page 300 that narcotization is a capillary phenomenon 

 — blocking of " active surfaces " by surface-active compounds. A relation 

 between narcotization and surface activity was noted by Traube forty 

 years ago: he found that, in homologous series of organic compounds, 

 the efficiency of narcotization increases with the length of the carbon 

 chain, and thus parallels surface activity. 



Narcotic poisoning is, in general, less specific than enzymatic poi- 

 soning, both in regard to the molecular structure of the poison and to 

 the constitution of the catalytic systems affected by it. However, the 

 field of narcotization is wide and also includes the action of such powerful 

 poisons or stimulants as morphine, strychnine and quinine, whose effect 

 on biocatalytical processes is more likely to be due to specific interactions 

 with definite catalysts, than to an indiscriminate surface-blocking action. 



True narcotization of animals is characterized by reversibility. How- 

 ever, large quantities of narcotics, or a prolonged exposure to any one of 

 them, usually cause irreparable damage or even death. Many substances 

 which have a narcotic effect on higher animals also inhibit photosynthesis 

 in plants; in this case, too, the initially reversible inhibition can lead to 

 an irreversible injury, if exposure lasts too long. Overdosage, as well as 

 differences in the sensitivity of different species (and perhaps even indi- 

 viduals), have caused a considerable confusion in this field of study. 



The narcotization of photosynthesis by chloroform Avas discovered by 

 Bernard in 1878. He found that photosynthesis is reversibly inhibited by 

 chloroform even before the latter affects respiration. On the other 

 hand, Schwartz (1881) found that the suppression of photosynthesis by 

 ether is associated with irreversible destruction of the tissue. Bonnier and 

 Mangin (1886) contradicted Schwartz and stated that, when used 

 carefully, ether as well as chloroform, causes only a reversible inhibition 

 of photosynthesis; similar results were obtained by Ewart in experiments 

 on the effect of ether on different mosses (1896) and of chloroform on 

 Elodea (1898). He found that even a short exposure of mosses to high 

 concentrations of narcotics leads to death, but that, if low concentrations 



* Bibliography, page 325. 



