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PROFESSOR A. M. PATERSON ON THE DEVELOPMENT OF 
white Rami arise from the second and third (and in man fourth (2)) sacral nerves 
which pass over without joining the ganglia ; becoming connected with the hypo¬ 
gastric plexus, tliey are distributed as the Nervi erigentes [vaso-inhihitorij fibres), 
'fhey are possibly also viscero-inhihitory. 
The only spinal nerves which come into direct communication with the sympathetic 
ganglia are the vasomotor fibres. In fact, so convinced is Gaskell of this that he 
maintains that “this chain might, therefore, be most appropriately called the chain 
of vasomotor ganglia, instead of the present meaningless title of main sympathetic 
chain.” Gaskell shows, moreover, that these vasomotor fibres are conducted along 
the sympathetic chain from their source to their distribution. In the anterior 
thoracic region they pass forwards along the chain to be distributed to the carotid 
and vertebral arteries, to the arm, and to the heart. In the posterior part of the 
thorax they pass backwards to the aorta, abdominal vessels, and lower limbs. 
The functions of the gangliated cord of the sympathetic thus appear to be :— 
1. To nourish the vasomotor fibres after converting them into non-medullated fibres ; 
and 2. To act as “a guiding rod” to direct the course of the stream of vasomotor 
fil>res emerging from the cerebro-spinal axis. 
B. Morphology. 
The prevailing notion among anatomists regarding the morphology of the gang- 
liatedcord of the sympathetic is one which springs from the analogy which it bears 
to the bilaterally gangliated chain in Invertebrates, and wdfich has been elaborated by 
1 ’alfour chiefly among embryologists (3). It is generally spoken of as being segmental, 
and the attempt is made to harmonise the arrangement of tlie ganglia with that of 
the vertebral somites. Instead, however, of presenting a distinctly metameric arrange¬ 
ment, there is anything but a correspondence with the segmentation of the body, as 
illustrated in the case of the spinal nerves or vertebrae. In the human subject, for 
example, in the neck there are only two, sometimes three, ganglia in the sympathetic- 
cord. The first is elongated, connected with four spinal nerves, and sometimes 
irregularly constricted, and so “ is favourable to the view that it may be regarded as 
consisting of several ganglia which have coalesced.” (4). The last cervical ganglion is 
frecpiently fused with the first thoracic. In the gangliated cord in the other regions 
tlie same irregularity is seen. Of the thoracic ganglia there are usually twelve, but 
variations are formed occasionally by the “ coalescence ” of adjacent ganglia. In the 
loins there are generally four ganglia, but the number is often diminished. They are 
sometimes even fused into a single ganglion, much elongated, passing over several 
vertebrae, and connected at intervals with the lumbar nei-ves. “ The sacral ganglia are 
usually four in number, but the variation both in number and Size is jnore marked 
than in the thoracic or lumbar ganglia” (4j. 
The assertion of Gaskell (1), which I shall venture in the secpiel to uphold fixun 
