644 
ON THE ACTION OF DIURETICS. 
nervous phenomena and anormal action of the heart, and copious 
serous dropsies, especially those dependent upon obstructed circu- 
lation, alterations of the heart, &c. In the last cases especially 
it is of importance to keep a narrow watch upon the general action 
of these medicines, because often at the time the blood and the 
central organ of the circulation are in conditions little favourable 
to vitality; and should we add to these existing causes of debility 
a diminution in the nervous influx, life might rapidly ebb away. 
This is what we occasionally remark when we use, in the smaller 
animals, squill, colchicum, and even digitalis, principally against 
ascites. The local condition of the disease amends rapidly at first, 
the belly diminishes in volume, the patients seem to be out of all 
danger, and, notwithstanding, death happens in some cases on a 
sudden and without discoverable cause. It is extremely probable 
that the cause is to be found in the depressive action of these me- 
dicines on a nervous system already in a state of debility from 
possessing a blood too serous and a circulation too feeble. 
Balsamic Diuretics. 
Diuretic medicines of this class comprise the resins, the gum- 
resins, benzoic or cinnamic acid, and the essential oils. Their 
effects differ greatly according to the doses in which they are ad- 
ministered. Locally, they act as irritants : they also excite in- 
tense gastro-intestinal irritation if given uncombined and in strong 
doses. Moreover, the portion absorbed exerts its influence upon 
the organic centres, obstructs pulmonary combustion, excites lively 
contractions of the heart, renders the pulse hard and frequent, sends 
the blood to the skin, through which it in part makes its escape, as 
well as through the bronchi, and at length gains an outlet through 
the urinary passages, the secretory organs of which it irritates, and 
so momentarily diminishes their action. 
If such medicines are administered in small doses, they become 
absorbed without creating any local irritation or well-marked ge- 
neral excitation. Having reached the blood, they make little effort 
to leave the circulatory current by the skin or the bronchi, being 
eliminated readily with the urinary discharges, which they render 
clear, soft to the feel, frothy, and to which they almost always 
communicate an agreeable violet odour. Lastly, these medicines 
stimulate the kidneys — in the long run, even irritate them — as well 
as the linings of the urinary passages, especially if these last are 
already inflamed, and the use of the medicine be long continued 
or given in large doses. But, in the contrary case, it is observed 
that such medicines render the urine more fluid and softer, in- 
somuch that it becomes a veritable topic to the passages over which 
