Commentary on Human Temperaments as They Depend on the Structure and Fabric of the Body

...greater nervous energy, there is a smaller action upon the common sensorium, and therefore a weaker sensation. I confess these are mere opinions, which, however, might pave the way for great discoveries if those anatomists to whom we owe so much in neurology would, with the utmost diligence in the dissections of human cadavers, inquire into the diverse thickness of the nerves, the external habit perhaps responding in some way to this, and the past history of the life of each body. I do not doubt that these inquiries will bring much light to the doctrine of temperaments, whose diversity depends upon the diversity of motion or sensation (§ 7).

That the cause of diverse sensibility is to be sought in the diverse condition of the nerves is not doubted; but does not irritability change with the same condition? Even if we do not wish to consider nervous force as the efficient cause of irritability l, nevertheless, with the exciting cause changed—which cannot be denied to the nerves—a diversity will appear in the effect, namely in those things which are carried out by motion, and therefore in all bodily functions. Indeed, this diverse condition of the nervous system perhaps brings no small difference to the faculties of the mind; because the common sensorium is, as I said above, to some extent subject to the power of the nerves, and with the thickness of the nerves increased, a greater quantity of a certain force seems to be drawn away from the brain m. Hence the greater sharpness of wit in the European, or the greater acuteness of the senses in an uncultivated man n; hence the vigorous strength of the body often joined with lesser wit.

c) Greater or lesser softness and thickness of the so-called cellular tissue, the net of Malpighi, the dermis, and the cuticle.

It has long since come to my mind: has nature perhaps intended the cellular tissue for a use other than what is commonly held? This tissue insinuates itself into the finest fibrils, and is so diffused everywhere that it constitutes the foundation of the entire fabric of the whole body, so that, by the help of this very cellular foundation, a connection and a certain path lie open between all parts of the body, whether they are otherwise by their nature most diverse, or most remote from each other by position o. Since it not only possesses a certain vital force but is also found in all organic parts—though not in those which lack vital forces—it perhaps performs a duty in common with the nerves, namely, that it brings vital forces to diverse parts, which afterward, according to the diverse structure of the part, manifest themselves in different ways. If indeed this opinion did not stand on firm ground, it is most certain, however, that one must look to the degree of softness and tenderness of this tissue, to the more tender structure of the parts arising thence to which it provides a foundation, and to the acquired...

l) Cf. Fontana, ibid., p. 48 ff.
m) Ebel, ibid., p. 14.
n) G. Forster’s Voyage Round the World, Vol. I, p. 373. Zimmermann, ibid., p. 608.
o) Blumenbach, ibid., p. 23, 24.