PULMONARY CAPILLARIES — EXPECTORANTS. 569 



juice, half an ounce; carbonate of potash, to saturation; decoc- 

 tion of sarsaparilla, ten drachms ; tincture of digitahs, ten to 

 thirty minims ; acacia mucilage, ten drachms : to be taken every 

 sixth hour. In such a prescription as this ^ve have the tincture 

 of digitalis, which will, in all probability, by contracting the 

 vessels, diminish the pulmonary congestion and lessen cough. 

 It is combined with carbonate of potash, and the effect of potash 

 upon the lungs is very marked indeed. For my knowledge of 

 its action I am indebted to Dr. Andrew Clarke. Its action is 

 perhaps best noticed in a patient suffering from consolidation 

 and softening of a limited portion of one lung. When such a 

 patient is in ordinary health, one may observe, on stethoscopic 

 examination, crepitant rales, limited to one spot. When he 

 catches cold, one may hear, in addition to those, dry rales 

 extending for some distance around the irritated spot, and the 

 cough at the same time becomes more frequent and troublesome, 

 while there is very little, if any, expectoration. If potash be 

 now given alone, or, still better, in combination with a vegetable 

 acid, the dry rfdes subside, and are replaced by moist ones, 

 which in the course of a day or two, as the potash is continued, 

 alter in character, giving one the impression of their being 

 caused by less viscid fluid. At the same time the expectoration 

 becomes more copious, and the cough less frequent and less 

 troublesome. Now is the time to alter the treatment, and for 

 the potash to substitute nitric acid. If this be given too soon 

 the cough, which had begun to get easier, will again become 

 drier and harder, but if it be administered at the proper moment 

 the cough becomes still less troublesome, the expectoration 

 diminishes, ana the moist rales disappear from the neighbour- 

 hood of the consolidated part of the lung, although they may 

 still remain, as before, in that part itself. Potash, then, has a 

 very marked effect in rendering the pulmonary secretion more 

 liuid and abundant, while nitric acid has an opposite effect. As 

 in many cases we wish to diminish the secretion rather than 

 increase it, it is nitric acid rather than alkalies which we 

 employ for long periods in the treatment of phthisis, as we have 

 already seen in the modified formula of Dr. Begbie's phthisis 

 mixture. 



