| 182 TERNSTRG@MIACEZ. 
always mixed with-a great excess of milk, and is used pure 
chiefly after dinner, when the presence of food in the stomach — 
retards its absorption and modifies its action. It is however 
eustomary for those who have mental or bodily work to 
perform before breakfast, to take a cup of “black coffee ” 7 
immediately on leaving bed. 
Theine and caffeine do not fully represent the sources fron 
which they are respectively obtained. The identity of these 
alkaloids in their physiological action does not imply a 
similar identity in tea and coffee. As little should we 
entitled to infer that all alcoholic drinks produce identical 
effects because they all contain alcohol ‘as their chief 
stituent. It is just as certain that tea and coffee differ in t 
action upon the human system as that Rhenish or Borde 
ao Moreover, not only are theine and caffeine pee . 
S with’ ther aad seitle su another; and yet the opetatid 
and from those of tea and coffee, in important particulars. 
is unquestionably a fact of the highest possible ee 
. all of these vegetable products, which are used by du 
and remote nations, should contain identical nroiandle 
ciples; but while we thus are led to admire the universal! 
of physiological laws, we should not lose sight of the pect li 
‘ities which distinguish these important articles of. ha 
= from one either (Stillé and Maisch.) 
Chemical composition.—From some experiments nad 
us with fresh tea leaves, which had been dried by exposure — 
air, and which had not been subjected to any manufactw 
- Operations, it would appear that gallic acid exists in the | 
leaf in. only minute traces ; but as the leaf during manuf 
of tea is exposed to a ‘igh: <i it is po 
that the gallic acid in commercial tea may be: presen 
— extent. BE ie _ no distinctive: 
