A second interesting addition to the Treatise of man that Descartes made in these letters concerns memory. Descartes now wrote that memories may not only be stored in the hemispheres, but also in the pineal gland and in the muscles (29 January 1640, AT III:20, CSMK 143; 1 April 1640, AT III:48, CSMK 146). Apart from this, there is also another kind of memory, “entirely intellectual, which depends on the soul alone” (1 April 1640, AT III:48, CSMK 146).