the arteries also determines the form and size of all the limbs; consequently the whole form of the body is determined by the course of the blood. Thus in general the blood, as it nourishes all the parts of the body, has also, as the primary fluidity of the organism, produced and framed them out of itself. And the nourishment which confessedly constitutes the principal function of the blood is only the continuance of that original production of them. This truth will be found thoroughly and excellently explained in the work of Rösch referred to above: "Ueber die Bedeutung des Blutes," 1839. He shows that the blood is that which first has life and is the source both of the existence and of the maintenance of all the parts; that all the organs have sprung from it through secretion, and together with them, for the management of their functions, the nervous system, which appears now as plastic, ordering and arranging the life of the particular parts within, now as cerebral, controlling the relation to the external world. "The blood," he says, p. 25, "was flesh and nerve at once, and at the same moment at which the muscle freed itself from it the nerve, severed in like manner, remained opposed to the flesh." Here it is a matter of course that the blood, before those solid parts have been secreted from it, has also a somewhat different character from afterwards; it is then, as Rösch defines it, the chaotic, animated, slimy, primitive fluid, as it were an organic emulsion, in which all subsequent parts are implicite contained: moreover, it has not the red colour quite at the beginning. This disposes of the objection which might be drawn from the fact that the brain and the spinal cord begin to form before the circulation of the blood is visible or the heart appears. In this reference also Schultz says (System der Circulation, § 297): "We do not believe that the view of Baumgarten, according to which the nervous system is formed earlier than the blood, can consistently be carried out; for Baumgarten reckons the appearance of the blood only from the formation of the corpuscles, while in the embryo and
