140 LIVERPOOL VETERINARY MEDICAL ASSOCIATION. 
to take on morbid impressions, there is a reaction or recoil in it, 
and the functions of ganglia are suspended. 
. The effect of this disturbance of ganglionic function is to 
cause dilatation of the peripheral vessels, especially the vessels of 
the udder ; the blood now rushes into the uncontrolled vessels, 
giving rise to the stage of engorgement. With this disturbance 
of power in the vessels of the udder more disturbance is set up 
in the other organs ; through reflex action excitement of the 
whole system is visible, and soon the diminished action of the 
spinal cord is apparent in the deficient power of co-ordination of 
muscular movement in the posterior extremities, and by the in¬ 
fluence the cord is known to exert upon the heart through the 
sympathetic system. 
The peculiar action of the cord in increasing the force and 
number of the pulsations of the heart, through what is known as 
the nerve of Cyon , by means of which the heart produces a reflex 
action, which causes the organs of the peripheral circulation to 
dilate, and consequently enables it to diminish the number and 
energy of its efforts. And this we find is what occurs at this stage 
of the disease. 
This, I believe, is the explanation of the brain symptoms, 
effusion arising from the paralysing reflex action of the nerve of 
Cyon ; the depressing nerve of the circulation producing deple¬ 
tion of the heart, and consequently diminution in the pressure of 
the blood, in general evidenced by the lowered temperature 
which now is present, and feeble beat of the central organ of the 
circulation, with coma, and most frequently death, when this 
stage is reached. 
In short, we have first excitement of the gland through the 
sympathetic action, ending in increased secretion of milk. 1st. 
stage. This is suddenly almost succeeded by engorgement of the 
gland through a reflex action of the ganglionic system allowing 
of the dilatation of blood-vessels, assisted by the increased amount 
of blood thrown back upon the system by the rapidly involving 
uterus, and consequently an arrest of secretion. 2nd stage. The 
functions of the cord are interfered with through the reflex 
action of the hypogastric or lumbar plexus, hence the loss of 
co-ordination of muscular action in the posterior extremities. 
3rd stage. This is succeeded by the peculiar action of the nerve 
of Cyon upon the peripheral circulation excited through the 
heart effusion into or on the soft brain tissue. 4th stage. 
This may be succeeded by permanent loss of brain power and 
collapse, or resolution, if the excitement has not been too strong 
or the effusions too extensive. 
Such in brief are my conclusions on the nature and cause of 
this disease. They are founded on practical observations and 
