65 
probable Action in Health and Disease. 
mations and general fevers. In both classes of diseases the character- 
istic general disturbance is due entirely to changes in the capillary 
vessels and in the nerves of the capillary vessels which I described 
in the first part of this paper, published in the January number of 
the Journal. 
Alteration of Nerve Fibres of Capillaries in Chronic Disease. 
In many forms of chronic disease the nerve fibres distributed to 
the capillary vessels, as well as those ramifying upon the small 
arteries and veins, degenerate and are at length destroyed. So that 
the variation in vascular tension and blood distribution which 
occur in the healthy state through the agency of these nerves 
cannot take place. If therefore in consequence of the body being 
exposed to very adverse conditions the circulation be much disturbed, 
the derangement cannot be compensated or the injury repaired. 
It too often happens that the damage is increased until sufficiently 
great to render a fatal result inevitable. 
In fatty degeneration of the capillary vessels and small arteries, 
the fine nerve fibres are also involved, and the mechanism for 
regulating the flow of blood through the small vessels is gradually 
impaired. In some cases the nerve fibres and the muscular fibres 
of the arterial coats have so completely degenerated that the 
distribution of blood is greatly impeded. The outline of the vessels 
becomes uneven, their coats thicker in some places than in others, 
and the lining membrane rough. The elasticity of the vascular 
walls is much impaired, and in not a few instances the tube is 
actually rigid. The nutrition of every organ in the body suffers 
partly from changes which affect the circulation of the blood, and 
in part from the altered composition of the blood itself, which is 
gradually induced by the deranged circulation occurring in the 
blood-forming and blood-changing organs. 
The condition of health is dependent upon the integrity of the 
nerve fibres distributed to the capillary vessels. It is therefore of 
the utmost importance to do all we can to keep these delicate nerve 
fibres in an active state. By exercise, cold bathing, and external 
rubbing, that amount of activity of the nerve fibres and change in 
the capillary circulation, is ensured at least once in the twenty-four 
hours that is required in order that the nerve mechanism which has 
been described may be exercised and its activity preserved. These 
nerve fibres are, as it were, the sentinels which give the earliest 
information of the dangerous proximity to the vessels of matters 
the entrance of which into the blood might occasion serious disease or 
cause death. So long as these sentinels are active and in thorough 
good working order, warning is given in time for the performance of 
acts which prevent the ingress of deleterious substances ; but if they 
