39 
thein is a better support under physical exertion than beer or fermented 
beverages. In our own day we have a good example of this natural 
selection. We can hardly take up a newspaper or magazine, or walk into 
a shop without seeing Liebig's extract of beef staring us in the face. Most 
people have used either that or the old fashioned beef tea, and have found 
it invaluable in times of sickness from its marvellous reviving properties. 
They have regularly taken it from simple experience, but at the same time 
without having the slightest knowledge as to how the beef tea does so 
much good, and the consequence is that almost every one thinks that beef tea 
is nutritious. It is however not so, for a healthy person would as certainly 
starve if fed only on that valuable preparation as if he were fed only on 
arrowroot or isinglass. Just like the tea, holly, coffee and cocoa, it only 
diminishes the wear and tear of the bodily organs, and we can live a great 
deal longer without ordinary food with an infusion of these plants 
containing thein or the extract containing kreatin than we can without. 
The same observations apply to our use of mustard. The essential oil of 
mustard is a chemical combination of sulphur and a base called allyl, and 
owes its flavour entirely to the last mentioned substance, and it is very 
remarkable to observe how different nations as distantly separated as those 
before mentioned have selected the very plants containing allyl for the 
purpose of giving a favorite relish to food, notwithstanding that the allyl 
compounds are extremely disagreeable and offensive in the pure state. 
Indeed in every part of the world the garlic flavour seems to be a general 
favorite : the Welshman lilies his leeks ; the Englishman his horse-radish 
and mustard; the Spaniard his onion and garlic; the Asiatic his assafoetida ; 
the Brazilian his Pitiveria and Sequieria. And all these have compounds of 
allyl in some form or other. The Israelites of old when leaving Egypt 
exceedingly regretted the loss of their leeks and onions. 
In the onion and garlic the allyl exists as a simple sulphide, and in the 
mustard and horse-radish as a compound of sulphur and cyanogen. How 
strange and inexplicable it seems then, that the simple and instinctive 
preference for a substance like this contained in a minute seed should 
become the source of an immense trade and give employment to many 
thousands of the working classes. 
