VALUE OF CALOMEL. 367 



the much-maligned calomel enters into the composi- 

 tion of most of the purgatives which enjoy the highest 

 repute amongst labourers and artisans, as well as the 

 powders which the mothers of families in every part 

 of England have found to be most beneficial in the 

 treatment of many of the ailments from which their 

 children from time to time suffer. Podophyllin is 

 also a valuable purgative, but somewhat uncertain in 

 its effects. It should be given in doses of not more 

 than one-third of a grain with colocynth, rhubarb, or 

 some other purgative. It should be distinctly borne 

 in mind that the object of giving a purgative is not 

 merely to unload the large bowel, for purgatives are 

 often eminently useful in cases in which there is cer- 

 tainly no fsecal accumulation. As has been already 

 intimated, by purgation fluid is rapidly removed from 

 the blood, and with the fluid so passing away many 

 other things, the presence of which is deleterious, 

 escape. 



The different classes of remedies, the action of 

 which has been referred to, effect a change in the 

 composition of the blood. Diuretics, sudorifics, and 

 purgatives promote the removal from the circulating 

 fluid of substances which accumulate in it, and which 

 are calculated to disturb healthy action if they are 

 not got rid of. No doubt, in perfect health, the exer- 

 cise taken, the fluid drank, and certain materials taken 

 in the food, promote the action of these emunctories 

 sufficiently ; but the artificial conditions, especially as 



