In order to study the metabolic aspects at the time of anaphylaxis, the author investigated the potential-time curve of animal organ tissues in in vitro anaphylactic Shock. Thin slices of the liver and the kidney of the guinea-pig (about 300 g) sensitized with the horse serum (0.25 cc) were suspended in Tyrode solution and then the horse serum was poured into it, thus causing anaphylactic shock. The results are summarized as follows: 1) Pouring of the horse serum caused the rise of potential of the sensitized liver slice, which might be considered to be caused by anaphylactic shock. 2) In the potential-time curve of the kidney, no noticeable rise was caused by pouring the serum. 3) The rise of potential by pouring the serum did not vary for 30 to 150 minutes after startin the measurement of potential. 4) The variation of the amount of the serum from 0.3 to 0.003 cc caused no noticeable difference in the rise of potential. 5) In the desensitized organ slice of the guinea-pig, pouring of the serum showed no change but a gradual fall in the potential-time curve.