1) Using the inactive cow sera as antigen, the latent cerebral local anaphylactic cats were made. Seven days and 120 days after the last sensitisation, the Ca and K contents in the cerebral grey and white matter were measured and compared with those of the normal. 2) The individual difference of Ca and K contents in the cerebral grey and white matter in the normal cats was little and constant, independent of their sex. No seasonal variation was remarked. 3) In the normal cat's blain, the Ca content was more in the grey matter than in the white matter, while the K content showed no difference. 4) In the latent cerebral local anaphylactic cats, the Ca content was less in both cases of the acute and the chronic types than the normal, in which it was less in the grey matter than in the white matter. 5) In the latent local anaphylactic cats, the K content showed no variation in the acute stadium comparing with the normal one, but in the chronic stadium it showed a considerable increase and the content in the grey matter was more than that in the white matter. 6) These decrease of Ca content and increase of K content indicate the accelerated activity of the brain and are considered to be due to the latent local anaphylaxis.