17G 
PROFESSOR A. M. PATERSON ON THE DEVELOPMENT OF 
seventh, as well as the eighth cervical, and first dorsal nerves : and the commissure 
connecting it with the middle cervical ganglion was double. The lumbar portion of 
the cord showed a faint indication of separation into four ganglia : was not joined by 
tlie last dorsal nerve : and was connected to the sacral portion by a double commis¬ 
sure. The existence of a fourth sacral ganglion was noted as doubtful. 
In an embryo of the fifth month (fig. 21, C.) the condition of the sympathetic cord, 
in some respects, more resembled the adult state than did the cord at the sixth 
month. The inferior cervical ganglion {I.G.), after having given off the vertebral 
plexus and branches to the eighth cervical and first thoracic nerves, w^as continued up 
into the neck in the form of two incompletely se23arated swellings, which were joined 
respectively by the seventh and sixth spinal nerves. The same ganglion was con¬ 
tinued down into the thorax as far as the junction of the second thoracic nerve— 
receiving roots also from the eighth cervical and first thoracic nerves,—where it gave 
rise to a commissure connected below with an elongated mass, joined by the three 
succeeding nerves. Below this were a series of co-termiiious ganglia, joined on the 
one hand by the lower thoracic nerves, and on the other giving off the roots of the 
Splanchnic nerves. The disposition of the cord in this portion of its extent appears to 
indicate the mode in which the individuality of the ganglia arises. The eleventh 
thoracic nerve was connected with two small ganglia ; the twelfth was joined by 
three branches to two other ganglia. In the loin a single oval mass was found, joined 
by long, fine branches from the lumbar nerves. This was joined by a delicate commis¬ 
sure to the sacral ganglia, which were three in number, the first connected with two, 
the other two each with one sacral nerve. 
These dissections could not, alone, be taken as proof of the original absence of 
segmentation of the sympathetic cord. When, however, they are compared with one 
another, and with the disposition of the adult cord, and are considered also in the 
light of the foregoing investigations, they lend support to the view that at an early 
date gangliation of the cord has not occurred, but that it is due to later collateral 
changes in the cord itself, and in the surrounding parts. 
The only observation I am acquainted wuth dealing with this question from the 
point of view of comparative anatomy is one by Swan. He figures the cord in the 
Snake as being imperfectly gangliated ; and he describes it as resembling a band 
rather than a chain of gangh'a. This observation I have had opportunities of 
repeating, with the result that I have found the cord precisely as he figures it. 
4. Cejyhalic and Caudal Terminations of the Sympathetic Cord. 
a. Cephalic termination; superior cervical ganglion; vertebral and carotid plexuses. 
The embryonic cord when first formed can, in transverse sections, be traced forwards 
as fiir as the cephalic border of the fime-limb : in sagittal sections to the level of the 
mouth, or first vertebral segment (Rat. 8 days, Plate 26, fig. 11). As growth continues 
