I should, however, add that some authorities have attributed exhilarating properties to the theobromine or nitrogenous alkaloid of cocoa. Its composition nearly resembles that of theine, as the following (from Johnstone) shows:
| Theine. | Theobromine. | ||
| Carbon | 49·80 | 46·43 | |
| Hydrogen | 5·08 | 4·20 | |
| Nitrogen | 28·83 | 35·85 | |
| Oxygen | 16·29 | 13·52 | |
| Total | 100·000 | 100·000 |
It exists in the cocoa-bean in about the same proportion as the theine in tea, but in making a cup of cocoa we use a much greater weight of cocoa than of tea in a cup of tea. If, therefore, the properties of theobromine were similar to those of theine, we should feel the stimulating effects much more decidedly.
The alkaloid of tea and coffee in its pure state has been administered to animals, and found to produce paralysis, but I am not aware that theobromine has acted similarly.
Another essential difference between cocoa and tea or coffee is that cocoa is, strictly speaking, a food. We do not merely make an infusion of the cacao-bean, but eat it bodily in the form of a soup. It is highly nutritious, one of the most nutritious foods in common use. When traveling on foot in mountainous and other regions, where there was a risk of spending the night al fresco and supperless, I have usually carried a cake of chocolate in my knapsack, as the most portable and unchangeable form of concentrated nutriment, and have found it most valuable. On one occasion I went astray on the Kjolenfjeld, in Norway, and struggled for about twenty-four hours without food or shelter. I had no chocolate then, and sorely repented my improvidence. Many other pedestrians have tried chocolate in like manner, and all I know have commended its great "staying" properties, simply regarded as food. I therefore conclude that Linnæus was not without strong justification in giving it the name of theobroma (food for the gods), but to confirm this practically the pure nut, the whole nut, and nothing but the nut (excepting the milk and sugar added by the consumer), should be used. Some miserable counterfeits are offered—farinaceous paste, flavored with cocoa and sugar. The best sample I have been able to procure is the ship cocoa prepared for the navy. This is nothing but the whole nut unsweetened, ground, and crushed to an impalpable paste. It requires a little boiling, and when milk alone is used, with due proportion of sugar, it is a theohroma. Condensed milk diluted and without further sweetening may be used.
In my last I promised the results of my investigations concerning the source of the sulphate of potash that I found replacing the natural tartrate in so many samples of sherry.
At first I hunted up all the information I could obtain from books
