PHYSIOLOGY OF THE NERVOUS SYSTEM. 
functions with which they have to do are, to a 
certain extent at least, influenced by this organ. 
Now it is almost certain that the heart and 
kidneys receive filaments from the cord which 
pass to them chiefly in the sympathetic nerve ; 
but as it is equally certain that they receive 
nerves from other sources likewise, as from the 
vagus nerve, and the proper filaments of the 
sympathetic, it would be erroneous, so far as 
anatomy teaches us, to affirm that these organs 
were wholly dependent on the cord. 
As regards the heart, observation and expe- 
riment on man and animals tend to confirm the 
conclusion which anatomy indicates, namely, 
that while the heart possesses a certain inherent 
power, and while it has an immediate connec- 
tion with the medulla oblongata and with the 
sympathetic, it is also not independent of the 
spinal cord. A slight injury to the cord ora 
chronic lesion of it affect the heart but little or 
not at all, because of its other sources of in- 
nervation; but a sudden and extensive injury 
to the cord, or a rapidly-developed destructive 
disease of it, materially depresses and weakens 
the action of the heart, and thereby the general 
circulation. The experiments of Clift, Wedeme- 
yer, and Nasse may be cited as leading dis- 
tinctly to this conclusion. Nasse’s experiments 
were on dogs, in which he maintained artifi- 
cial respiration; he found that as soon as the 
spinal cord was destroyed, the heart failed so 
completely that the jet of blood from the femo- 
ral artery, which before had gone to a distance 
of some feet, could not reach as many inches, 
or the blood did not escape per saltum from 
the wounded artery. In performing a similar 
experiment, Longet compared the action of the 
heart in two dogs, destroying the cord in one, 
but allowing it to remain intact in the other, 
and he found that in the animal whose spinal 
cord was destroyed the cardiac movements be- 
came enfeebled in a very striking manner, 
when compared with those of the animal 
whose cord was left uninjured. 
If, then, we can prove that the spinal cord 
exercises an influence upon the central organ 
of the circulation, there can be no doubt that 
its power extends to the peripheral parts of the 
circulating system, to the capillary vessels, 
and, therefore, that injury or disease of it, espe- 
cially if sudden or extensive, must to a certain 
extent affect the functions which are performed 
through the agency of these vessels, namely, 
nutrition, calorification, and secretion. 
It seems most probable that it is only in this 
secondary manner that the influence of the 
spinal cord becomes extended to these func- 
tions, and that they suffer, when, through lesion 
of the cord, this influence has been greatly 
diminished or removed. The indications of 
its connection with nutrition and calorification 
are derived from the wasting and the coldness 
which are manifest in the paralysed parts when 
there is lesion of the spinal cord of a depress- 
ing kind. Sometimes, too, the nutrition of 
these parts is so feeble that gangrenous sloughs 
are formed on parts exposed even to slight 
pressure. This is more apt to be the case where 
the disease of the cord has been of a destruc- 
VOL. III. 
721s 
tive kind, and has involved a considerable 
portion of the organ and of the roots of its 
nerves. 
The influence of the spinal cord upon secre- 
tion has been inferred chiefly from the frequent 
occurrence of an alkaline state of urine in con- 
nection with injuries of that organ, and less 
frequently in diseased states of it. The urine, 
when passed, is found to be highly alkaline 
from the existence in it of a large quantity of 
carbonate of ammonia. The urine, in cases 
of this kind, is very apt to contain more or 
less of what has been very commonly, although 
erroneously, called ropy mucus, which is in 
truth pus formed from the mucous membrane 
of the bladder. This membrane is irritated 
and inflamed by the sojourn in it of the urine 
which the paralysed bladder is unable to expel. 
The secretion of a large quantity of phos. 
phate of lime and of mucus, and afterwards of 
pus, is provoked by inflammation of the vesical 
mucous membrane. And the addition of these 
matters to it, especially the former, neutralises 
all free acid and gives rise to decomposition of 
the urea, and the production thereby of car- 
bonate of ammonia. The alkalescence of the 
urine favours the precipitation of the triple 
phosphate. Hence urine obtained from pa- 
tients suffering under spinal disease resembles 
very closely that of patients with diseased blad- 
der without spinal disease. We may see in it 
mucus or pus globules, triple phosphates, blood 
particles, and amorphous masses of phosphate 
of lime mingled with the mucus. But in 
some instances the period of the sojourn of 
the urine in the bladder appears too short for 
these changes to take place; and hence it has 
been supposed that the urine may be secreted 
alkaline by the kidneys. Mr. Smith, of St. 
Mary’s Cray, in Kent, made experiments on 
this subject by washing out the bladder care- 
fully with warm water several times, withdraw- 
ing the water each time and testing for am- 
monia until all indication of its presence 
ceased. He then injected a small quantity of 
clear water, and allowed it to remain fifteen or 
twenty minutes; it was then drawn off, and the 
odour of ammonia could be distinctly per- 
ceived. It is to be regretted that a more accu- 
rate test of the presence of ammonia had not 
been used. Admitting, however, that am- 
monia did exist in this fluid, the experiment 
by no means disproves the formation of am- 
monia in the bladder. So small a quantity 
of urine as might trickle into the bladder in 
twenty minutes might readily be neutralised 
and decomposed by any alkali or mucus pre- 
sent in the bladder which might have eluded 
the previous washing out of that organ. If the 
secretion of urine in the alkaline state were 
common, it might reasonably be expected that 
such urine would be more frequently met with 
than it is in spinal complaints. Dr. Golding 
Bird, indeed, states that in the case of a woman 
in Guy’s Hospital, labouring under complete 
paraplegia, and passing, with the aid of a ca- 
theter, fetid, alkaline, and phosphatic urine, he 
washed out the bladder with warm water, and 
after the lapse of half an hour obtained some 
Q 7 RRR 
