PHYSICO-CHEMICAL PROPERTIES. 95 



protoplasm only with difficulty. Since, however, the 

 esters are saponified in the organism, in consequence of 

 which the anions of the acids become free, a physiological 

 ion effect might nevertheless be expected under favor- 

 able conditions, even after the administration of esters. 

 Such an effect will become apparent, however, only when 

 in a readily dissociated ester some anion is present that 

 has characteristic physiological properties and is suf- 

 ficiently active physiologically to show itself, otherwise 

 the narcotic and circulatory effects common to all esters 

 conceal the intoxication picture. If for purposes of 

 comparison experiments are made with sodium sulpho- 

 cyanate and the amyl ester of sulphocyanic acid, a typical 

 sulphocyanate intoxication occurs in both cases. Careful 

 analysis shows that this consists in a fall in blood-pressure 

 brought about through a decrease in the energy of the 

 heart muscle, a subsequent increase in pressure through 

 stimulation of the vascular centres and great, principally 

 central, stimulation of the vagus. While, however, the 

 intravenous injection of two to three drops of the ester 

 suffice to bring about a rapid and fatal intoxication in 

 a medium-sized dog, eight to ten grams of sodium sulpho- 

 cyanate must be introduced intravenously to bring about 

 the same effect. This enormous difference in toxicity 

 shows that in the amyl-sulphocyanate intoxication the 

 ester readily enters the cells, because of its solubility in 

 the lipoids, and that not until it has arrived in the cells 

 are its anions set free. These same ions, when already 

 formed, enter the cells only with difficulty, in consequence 

 of which the body must be charged with a great excess 

 of sodium sulphocyanate in order to bring about the 

 same degree of intoxication, 



