TRANSACTIONS OF THE SECTIONS. 29 
 eular contraction is always pence by a phenomenon analogous to the electrical 
_ spark, and that the electrical current does but modify the nervous excitability. On 
_ these facts M. Matteucci establishes a simple theory of electro-physiological pheno- 
- mena. In the last part of his communication he treated of inducted contraction; and 
after having demonstrated that these phenomena cannot be explained in supposing 
an electrical discharge of any kind indiscriminately, he concluded that inducted con- 
traction is an elementary phenomenon of the nervous power, which acts in muscular 
contraction, and is analogous to all the actions of induction of physical forces. 
On the Identity of certain Vital and Electro-magnetic Laws. 
By JosEru Butiar, M.D. 
The object of this paper was to show that the direction and formation of bleod- 
vessels and the capillary circulation through them, which is independent of the pro- 
pulsive power of the heart, are in accordance with laws of the vital force, identical in 
their direction and relation to each other with those of the electro-magnetic force. 
In such an investigation the forms of bodies were considered of the highest import- 
ance, Growth is invisible, but the forms it produces are the evidence of the unseen 
vital force, and by announcing its direction, determine its law. To seek therefore the 
primary forms of which others are mere varieties, and to ask, “ From what direction 
of the living force does such a form derive its shape?” is a legitimate step towards the 
discovery of the cause of that form, the “formal cause” of Bacon, or the law in mo- 
dern language. The formation of blood and blood-vessels in the germinal membrane 
which grows round the embryo during the incubation of a hen’s egg, was taken as a 
simple type of this process. The small whitish disc on the yolk-bag (the cicatricula), 
is the spot where the vital changes begin. The embryo occupies the centre of this 
spot, and becomes the centre of the vital force excited by the mother’s warmth. From 
this centre the force is communicated to the yolk-bag. The disc enlarges, still keep- 
ing its circular form, and marked by concentric circles more or less perfect. The disc 
is produced by the conversion of the yolk into cells, which adhere as a thin circular 
layer. The circular form of this disc and the general concentric arrangement of the 
cells, were considered to indicate that the lines of vital force which arranged and pre~ 
served that form were circular. The next step is:the conversion of a portion of these 
cells which form the disc into blood and blood-vessels, The trunks pass in the direc- 
tion of radii of the original disc and central germ. The main trunks unite at the 
central heart, which is at first only a bent portion of the common trunk. The capil- 
laries inosculate at the circumference; thus the vessels form a complete circle. This 
circular arrangement of the vessels as radii indicates a second circular force at right 
angles to the plane of the former one. The vessels are formed thus. Those called 
by Harvey “ vasa lutea” are coarse, and the stages in their formation are more easily 
watched, They are formed in the substance of the disc, and out of the same mate- 
rial,—the cells of the yolk, These cells continuing to accumulate, some are arranged 
as cylinders, then in succession as half-circles, circles, net-work, and trunks conver- 
_ ging to the central embryo. At this stage each vessel is a coarse yellowish cylinder, 
' with a red streak down its axis. Externally it is composed of cells of various sizes, 
which can easily be brushed off from the semi-transparent tube which they cover, and 
_ which is composed of smaller cells, and contains the red blood flowing towards the 
' centre. The inference drawn was, that this tube, formed of cells around the current, 
is the evidence of a circumferential force around the current, arranging the cells as 
- atube. It was next shown that such a direction and relation of the vital force in 
_ arranging the disc and its vessels were in accordance with the direction and relation of 
_ the electro-magnetic force. The law of this double force, which bears on the present 
inquiry, is, that in order to act both currents must circulate, that is, each must return 
into itself. That the galvanic force must circulate, is evident from the construction 
_ of a galvanic cell. The magnetic force accompanying the galvanic obeys the same 
law. It also circulates, but in a plane at right angles to the galvanic. Dr, Wollaston 
called it, in consequence of its cireulation, verfiginous magnetism. These two cur-- 
_ xents are inseparable. They are directive forces, or carrying, according to the con- 
| dition of matter on which they act. What is true of the magnetic current circulating 
' round a single wire conyeying the galvanic current, applies to two or more wires if 
