71 
has a more considerable nutritive value than the pith, as you may judge 
by the following table : 
Water Crust = 17.15 pith = 44-45 
Insoluble nitrogenous subst " = 7.30 " = 0.92 
Soluble " " " = 5.70 " = 0.75 
Soluble non-nitrogeous " ' = 3.88 " = 3.79 
Starch " -62.58 " =43-55 
Fatty substances " = i.lS " = 0.70 
Salts " = 1. 21 " = O.84 
Potatoes for 100 parts contain 2 parts of nitrogenous substances and 
21 of carbo-hydrates. Rice has 5 parts of albuminoids and 83 carbo- 
hydrates. 
Among the fats I shall mention butter, which contains 01 per cent. 
of fatty substances ; cheese, which contains 24 per cent, of fat, besides 
33 per cent of nitrogenous substances. 
My intention is not to dwell at any length on fruits, wishing only 
to remind you that they introduce into our economy salts of sodium 
and potassium, useful to nutrition, and since I am speaking of salts, I 
wish to point out the importance of common salt, and of all mineral 
matters in alimentation. These substances are just as necessary as the 
reparative and respiratory aliments. Forster has given pigeons, mice 
and dogs a food very poor in mineral matters, and he has observed that 
mice lived 21 to 30 days only, pigeons 13 to 29 days, and dogs 26 to 
36 days. 
According to Barbier, man must take daily within 24 hours, 12 to 
20 grammes of salts, either pure or mingled with food. When for one 
reason or another man cannot take the necessary quantity of salts, the 
same accident happens as with other animals, he falls into a state of 
weakness and languor, offering, after a while, all the symptoms of 
anemia, owing to the dimunition of albumen and blood corpuscles. 
With regard to the importance of salts in alimentation, I cannot 
resist the desire of saying a few words about " scurvy," a disease I par- 
ticularly studied within the last few years. This disease, which for- 
merly was the terror of navigators, exists nowhere, so to speak, except 
in Canada, where it pretty severely treats, almost every year, the rafts- 
men who spend the winter in the midst of our forests. You have all 
heard of that disease called " blackleg " by our " voyageurs," which 20 
