The toxicity and safety of food additives are tested in our country by such procedure
as determining the lethal dose to animals or determining the acuteness，subacuteness，or chronicity of their effects. That is， the methods employed are for the most part
pathologic and not physiologic in nature. At present， however， many authorized
additives commercially available on the market are found to be toxic， presumably
because of the weakness of the tests required for granting authorization. Censidering it important therefore to develop physiologic methods of testing，the authors seek to clarify the effects of these additives on the circulatory and nervous systems and the liver of the bullfrog and to proceed further to experimentation with mammals. In our first
report，their effects on the contractility of the heart of the bullfrog will be described.