884. REPORT—1899. 
muscles in the skin will cause the flesh to creep; other similar small muscles are 
attached to the hairs; ’tis these will make 
‘Thy knotted and combinéd locks to part, 
And each particular hair to stand on end, 
Like quills upon the fretful porpentine.’ 
The involuntary tissues, although not under the prompt and immediate control 
of the will, are under the control of the higher centres of the brain. They are 
particularly responsive to the emotions ; and in so far as we can call up emotions, 
we can play upon them at will. The ease with which nervous impulses pass along 
given tracts depends, amongst other things, upon use. And so it appears that our 
great-grandfathers wept and our great-grandmothers fainted with an ease which 
we should require assiduous practice to attain. 
Further, you may note that the contraction of involuntary muscle caused by 
an emotion may in its turn set up nervous impulses, which pass back to the brain 
and give rise to vague and curious feelings, feelings often lending themselves to 
effective literary expression :— 
‘Where our heart does but relent, his melts; where our eye pities, his bowells yearn. 
I must ask your forgiveness for mentioning so many well-known facts in the 
sketch which I have just given of the involuntary tissues. But I hope it will take 
from you all excuse for not understanding the rest of what I have to say. 
The arrangement of the involuntary nervous system presents some peculiar 
characters. The most distinctive of these is that the nerves, after they leave the brain 
or spinal cord, do not run interruptedly to the periphery; they end in nerve-cells, 
and the nerve-cells send off the fibres which run to the periphery. The most direct 
proof of this lies in the fact that a certain amount of nicotine prevents the central 
nervous system from having any influence on the peripheral structures—i.e. the - 
line is somewhere blocked ; it can be shown, speaking generally, that there is no 
block on either side of the ganglia, so that it must be in them. The actual point 
of attack of the nicotine appears to be the connections made by the central nerve- 
fibres with the peripheral nerve-cells. Thus all nerve-impulses, which pass from 
the brain or spinal cord to unstriated muscle or glandular tissue, pass through an 
intermediate station on their way. In this, as in some other respects, the arrange- 
ment of the involuntary nervous system is more complex than that of the voluntary 
nervous sytem ; in the latter the motor nerve-fibres run direct to the tissue and 
have no nerve-cells on their course. The nerve-cells which form the intermediate 
stations for the involuntary nerve-fibres are grouped together into ganglia; and so 
we may call the nerve-fibres which run from the brain or spinal cord to the nerve- 
cells pre-ganglionic fibres, and the nerve-fibres which run from the ganglia to the 
peripheral tissues post-ganglionic nerve-fibres. 
The involuntary nervous system is divided into at least two subdivisions. 
The most extensive of these is what is called the sympathetic nervous system. The 
pre-ganglionic fibres of the sympathetic arise from a limited portion of the spinal 
cord. They arise from that part of the spinal cord which is in the region of the 
chest and the small of the back—z.e. roughly from the part which lies between the 
origin of the voluntary nerves for the arms and the origin of the voluntary nerves 
for the legs. he fibres given off by the ganglia of this system—i.e. the post- 
ganglionic fibres—run to the involuntary tissue in all parts of the body. 
The Cranial and Sacral Systems.—The second division of the involuntary 
nervous system consists of two parts; one part—the cranial—arises from the 
brain—z.e. above the origin of the sympathetic; the other—the sacral—arises 
irom the end of the spinal cord —z.c. below the origin of the sympathetic. 
Each supplies a limited and different part of the involuntary tissue of the body, 
but both together supply a portion only of it. Taking the distribution broadly, 
they supply the muscular coats of the alimentary canal and certain structures 
connected developmentally with the anterior and posterior portions of it. They are 
especially connected with these terminal portions ; they send numerous nerve-fibres 
to them; whereas they send but few to tne intérvening portion, and none at all to 
| 
