SENNA TREE. 139 



Arts, &c. which has offered a reward to those who succeed in the 

 attempt, will be ultimately accomplished. 



The leaves of senna, which are imported here for medicinal use, 

 have a rather disagreeable smell, and a subacrid bitterish nauseous 

 taste : they give out their virtue both to watery and spirituous men- 

 strua, communicating to water and proof spirit a brownish colour, 

 more or less deep according to the proportions ; to rectified spirit a 

 fine green. 



Senna, which is in common use as a purgative, was first known to 

 the Arabian physicians, Serapion and Mesue ; and the first of the 

 Greeks by whom it is noticed is Actuarius, who does not mention 

 the leaves, but speaks of the fruit. Mesue likewise seems to prefer 

 the pod to the leaves, as being a more efficacious cathartic, but the 

 fact is contrary, for it purges less powerfully than the leaf, though it 

 has the advantage of seldom griping the bowels, and of being without 

 that nauseous bitterness which the leaves are known to possess. 

 How bitterness aids the operation of senna is not easily to be under- 

 stood ; but it is observed by Dr. Cullen, that " when senna was in- 

 fused in the infusum amarum, a less quantity of the senna was ne- 

 cessary for the dose than the simple infusions of it." The same au- 

 thor has remarked, " that as senna seldom operates without much 

 griping, its frequent use is a proof how much most part of practi- 

 tioners are guided by imitation and habit." Senna, however, when 

 infused in a large proportion of water, as a dram of the leaves to 

 four ounces of water, rarely occasions much pain of the bowels, and 

 to those who do not object to the bulkiness of the dose, may be found 

 to answer all the purposes of a common cathartic. For covering the 

 taste of senna, Dr. Cullen recommends coriander seeds ; but for pre- 

 venting its griping, he thinks the warmer aromatics, as cardamoms 

 or ginger, would be more effectual. The formulae given of the 

 senna by the Colleges, are those of an infusion, a powder, a tincture, 

 and an electuary. Its dose in substance is from a scruple to a 

 dram. 



[Lezeis, Cullen, fVoodville* 



