SCIENCE. 



75 



SCIENCE AT BREAKFAST. 

 By The Editor. 



The sterling goodness of Dr. Johnson's heart, not- 

 withstanding many apparently blunt demonstrations to 

 the contrary, was never more clearly demonstrated, than 

 when he remarked to Boswell, " I encourage this house, 

 for the mistress of it is a good civil woman, and has not 

 much business." 



The house referred to was the "Turk's Head Coffee 

 House." But coffee houses, nay coffee drinkers, have 

 much changed in outward form since the days of the 

 sturdy old philosopher. The beau and the belle no 

 longer, in picturesque costumes, discourse scandal, sip- 

 ping the Eastern beverage from exquisite specimens of 

 china ware, and tea and coffee, no longer a luxury, are 

 now enjoyed by the toiling millions, and esteemed a 

 blessing by all classes. 



Although tea and coffee is universally used by the civ- 

 ilized nations of the world, few understand the natural po- 

 tent properties of these substances, or are even conscious 

 of their powerful action upon the human system, and as 

 it is a subject interesting to so many, I offer the following 

 sketch, treating of the more important points. 



Coffee, tea and chocolate all contain in common a ni- 

 trogenised basis, to which they owe most of their impor- 

 tant chemical properties. Tea and coffee even contain 

 the self-same basis, denominated indiscriminately theine 

 or caffeine. In chocolate the cocoa principle called theo- 

 bromine is richer in nitrogen than the theine. 



The chemical constituents of these substances are as 

 follows : While in tea the basis is combined with tannic 

 acid, in coffee it forms a salt, with a peculiar tannic acid, 

 containing a greater proportion of nitrogen, which to- 

 gether with tannio-caffeic acid is united with potash 

 into a so-called double salt. Tanno-caffeic acid when 

 roasted, develops the agreeable odor of coffee. 



Not only the same basis, but also two similar organic 

 acids, one contained in tea, the other in coffee, increase 

 the conformity, between the leaves of the former and the 

 beans of the latter. 



Legumin, cellulose, gum, sugar, citric acid in addition 

 to oleine, and what is called palm -fat, accompany the or- 

 ganic acids and the theine of the coffee beans. 



But the tea leaves, apart from the basis and the acids, 

 are composed of albumen, cellulose, gum and wax, the 

 green pigment of the plant and the volatile oil of tea 



This peculiar oil is the principal source of the aroma 

 of tea, by which, in spite of the conformity between tea 

 and coffee, it essentially differs from the latter. 



The inorganic constituents of tea and coffee are more- 

 over different. While in coffee, chlorine, phosphoric and 

 sulphuric acids are combined with potash, lime, magnesia 

 and oxide of iron ; tea contains another inorganic acid 

 besides, consisting of manganese and a large proportion 

 of oxygen. 



So much for the chemical constituents of coffee and 

 tea. Let us now examine their peculiar properties and 

 nutritive qualities. 



Chocolate from its large proportion ot albumen is the 

 most nutritive beverage, but at the same time from its 

 quantity of fat, the most difficult to digest. But its aro- 

 matic substances strengthen the digestion. A cup of 

 chocolate is an excellent restorative and invigorating re- 

 freshment even for weak persons, provided their diges- 

 tive organs are not too delicate. Cardinal Richelieu 

 attributed to chocolate his health and hilarity during his 

 later years. 



Tea and coffee do not afford this advantage. Albu- 

 men in tea leaves, and legumin in coffee berries, are 

 represented in very scanty proportions, for while in the 

 former the albumin is coagulated by boiling water, in the 

 latter the legumin is prevented from being dissolved by 

 the lime with which it is combined. 



The praise of tea and coffee as nutritive substances is, 



therefore, hardly warranted, because, as restoratives for 

 the body, the alimentary principles and not the elements 

 are to be taken into account. The former principle cannot 

 be ascribed to " Theine," which is excreted again as urea 

 with surprising rapidity, and to this swift transformation 

 tea and coffee owe their diuretic action, which is consid- 

 erably assisted by the warm water of the infusion. 



Tea and coffee, though of themselves not difficult of 

 digestion, tend to disturb the digestion of albuminous 

 substances by precipitating them from their dissolved 

 state. Milk, therefore, if mixed with tea or coffee, is 

 more difficult of digestion than if taken alone, and coffee 

 alone without cream promotes digestion after dinner by 

 increasing the secretion of the dissolving juices. 



The volatile oil of coffee and the empyreumatic and 

 aromatic matters of chocolate accelerate the circulation, 

 which, on the other hand, is calmed by tea. 



Tea and coffee both excite the activity of the brain and 

 nerves. 



Tea, it is said, increases the power of digesting the 

 impressions we have received, creates a thorough medi- 

 tation, and, in spite of the movements of thoughts, per- 

 mits the attention to be easily fixed upon a certain sub- 

 ject ; a sense of cheerfulness and comfort ensues, the 

 functions of the brain are set in motion, the thoughts are 

 concentrated and not apt to degenerate into desulto- 

 riness. 



On the other hand, if tea is taken in excess, it causes 

 an increased irritability of the nerves, characterized by 

 sleeplessness, with a general feeling of restlessness and 

 trembling of the limbs ; spasmodic attacks may arise, 

 with difficulty of inspiration in the cardiac region. The 

 volatile oil of tea produces heaviness in the head, first 

 manifesting itself in dizziness and finally in stupefaction. 



These symptoms have been called an evidence of a 

 real tea intoxication. Green tea, which contains much 

 more of the volatile oil than the black, produces these 

 obnoxious effects in a far higher degree than the latter. 



While tea principally revives the faculty of judgment, 

 and adds to this activity a sensation of cheerfulness, 

 coffee acts also on the reasoning faculties, but without 

 communicating to the imagination a much higher degree 

 of liveliness. 



Susceptibility to sensuous impressions is intensified by 

 coffee ; the faculty of observation is therefore increased, 

 while that of judgment is sharpened, and the perceptions 

 adopt more quickly certain forms, activity of thoughts 

 and ideas is manifested, a mobility and ardor of wishes 

 and ideals, which are more favorable to the shaping and 

 combination of already premeditated ideas than to a 

 calm examination of newly originated thoughts. 



Coffee, also, if taken in excess, produces sleeplessness 

 and many baneful effects very similar to those arising 

 from tea drinking. Coffee, however, produces greater 

 excitement, and a sensation of restlessness and heat 

 ensues. For throwing off this condition fresh air is the 

 best antidote. 



Much depends upon the proper roasting of coffee, in 

 which process it loses weight but increases in bulk, 

 two pints ot unroasted berries giving three pints when 

 roasted. 



Several empyreumatic substances created by roasting 

 produce the reddish or brown color, and the tanno- 

 caffeic acid, altered by roasting, produces the aroma ; 

 the sugar loses a part of its amount of hydrogen and 

 oxygen, and is thus decomposed into burnt sugar or 

 caramel. 



Liebig states that the berries should be roasted until 

 they are of a dark brown color. In those which are too dark 

 there is no caffeine ; and if they are roasted black, the 

 essential parts of the berries are entirely destroyed, and 

 the beverage prepared from them does not deserve the 

 name of coffee. This fact should be noted by drinkers 

 of caffe-noir. 



The berries of coffee when once roasted, lose every 



