. 233 



ACTION AND USES. 

 1. IMMEDIATE LOCAL ACTION AND USES. 



Given internally, senna stimulates the muscular coat of the 

 intestine, apparently by local reflex action, originating in the 

 mucous surface of the bowel itself; and produces brisk 

 peristaltic movements and purgation within four or five hours. 

 The colon is chiefly stimulated, hurrying downwards the fluid 

 contents received from the ileum, which appear as very thin 

 copious yellow stools, with excess of soda salts and digestive 

 products, but no special increase of bile. Full doses cause re- 

 peated evacuation and griping, but no inflammation of the 

 mucous surface. The pelvic structures may, however, become 

 hypersemic, leading to haemorrhoids and the appearance of the 

 menses. Constipation does not follow the use of senna. 



Senna is never given alone, but always with a carminative to 

 prevent griping, and frequently with other purgatives, as in the 

 compound mixture. It is one of the most useful of purgatives. 

 It is very extensively prescribed to complete the effect of mer- 

 curial and other duodenal purgatives, given several hours 

 before. It affords at once a rapid and a safe purge at the com- 

 mencement of febrile attacks in children, in local inflamma- 

 tions, and in cerebral congestion. As an habitual laxative in the 

 form of Pulvis Glycyrrhizae Compositus, senna is most valuable 

 as a simple stimulant of the muscular coat, which neither loses 

 its effect by use, nor produces subsequent constipation. Com- 

 bined with bitter and other stomachics, it is useful in atonic 

 dyspepsia, its laxative effect being increased by acids but 

 diminished by alkalies. 



ACTION IN THE BLOOD, SPECIFIC AND REMOTE LOCAL ACTION. 



Cathartic acid and chrysophanic acid enter the blood, pass 

 through the tissues, and are excreted by the kidneys and mam- 

 mary gland ; the cathartic acid purging infants at the breast, 

 tlie chrysophanic acid staining the urine yellow. Senna 

 purges animals when injected into the veins. 



Haematoxyli Lignum LOGWOOD. The sliced 

 heark wood of Hsematoxylum Campechianum. Im- 

 ported from Campeachy. Honduras, and Jamaica. 



Characters. The logs are externally of a dark colour, 

 internally they are reddish-brown. The chips have a feeble 

 agreeable odour, and a sweetish taste. A small portion chewed 

 imparts to the saliva a dark pink colour. 



