MEDICINAL EFFECTS. 267 



were also made with decomposing meat soups, which were 

 actually swarming with various forms of micro-organ- 

 isms, the results obtained showing that the vitality of the 

 spores contained in the fluid was greatly diminished after 

 a short exposure, but was not completely destroyed until 

 after an exposure of many days. 



It fnay at first sight seem irrational that a substance 

 which restricts tissue-waste should be used for the pur- 

 pose of quickening certain other functions, more espe- 

 cially those of the brain, yet the physical activity, mental 

 exhilaration and wakefulness it causes explains the liking 

 for it shown by so many men of science, poets, scholars 

 and others devoted to thinking. But all^ of these 

 occupations involve increased waste of tissue in the 

 brain as well as of the spinal marrow, the very 

 action which coffee is said to restrain, so much so 

 that to reconcile these apparent incongruities, it has been 

 maintained that coffee does not act primarily as a cere- 

 bral stimulant, but only secondarily by removing the 

 vascular plenitude occasioned by prolonged study, by 

 a full meal, and especially by opium, alcohol, or other 

 agents which directly tend to load the brain with blood, 

 so that when taken on an empty stomach it does not 

 quicken the functions of the brain, but on the contrary 

 renders it dull and inapt for steady thought, creating 

 nervousness and general debility and frequently causing 

 hemicrania. 



During digestion, however, the case is different, par- 

 ticularly if a full and stimulating meal has been taken, 

 the mind grows dull and sluggish, a tendency to sleep 

 arises, and everything indicates an increased amount of 

 blood on the brain, it being in like manner that prolonged 

 mental labor produces cerebral plenitude and drowsiness. 

 It is this condition apparently which coffee corrects 



