MATEFtiA MEDICA, AND THERAPEUTICS. 
735 
before they are eaten ; but this is not very convenient in many families, and the 
colour of the potato is not quite so agreeable as that of those which have been 
boiled after peeling. When they are peeled before boiling, and particularly 
when they are small, and the operation is performed carelessly, from one-third 
to one-fourth of the whole weight of the potato is lost, and if there be no pig to 
eat the peelings the whole is wasted; whilst the weight of the peel which is 
removed after boiling would not amount to more than 1 oz. in the pound. When 
potatoes have been roasted, the loss in weight from the skin and drying is more 
than one-fourth of the weight before cooking. An average sample of potato, 
after it has been peeled, contains 11 per cent, of carbon and 0’35 per cent, of 
nitrogen ; and hence in each pound there are 770 grains of carbon and 24 grains 
of nitrogen, and it is greatly inferior to bread. The economy of its use depends 
upon its cost, so that in times when potatoes are sold at |(/. and Id. per lb. they 
are a very dear food as compared with household flour, whilst they are a very cheap 
food when produced by the labourer at the cost of the “seed” and the rent of 
land. Thus, at ft/, per lb., only 1024 grains of carbon and 32 grains of nitrogen 
will be obtained for Id .; when the cost is Id. per lb., the quantities will be re¬ 
duced to 770 grains and 24 grains. When the labourer, however, can obtain 
60 bushels of potatoes from a quarter of an acre of land, at a cost of about 305. 
for seed and rent, he will have more than 7 lb. of potatoes for U., and the quan¬ 
tity of carbon and nitrogen thus obtained for that sum be 5770 grains and 200 
grains. If, however, he were to sell a large part of his crop at the market price, 
he could procure with the money thus obtained far more nutriment in the form 
of flour than would have been derived from that portion of his potatoes. The 
weight of potatoes which alone would supply the daily nutriment required by a 
man would be about 6 lb. in reference to the carbon, and 8 lb. in reference to 
the nitrogen ; but when a labourer in the west of Ireland lives upon this food he 
is allowed 10^ lb. daily, besides a large supply of buttermilk; and as both of these 
kinds of food are cheap in that locality, the proceeding is even then an econo¬ 
mical one. 
Australian Iseeches. 
A Melbourne Journal says that this branch of trade has grown to pretty ex¬ 
tensive proportions, both as to the number collected and the distances to which 
they are forwarded. The trade is principally carried on in connection with the 
operations of the Murray River Fishing Company, the fishermen employed by the 
company turning their attention,at seasons unfavourable to the fishery, to the col¬ 
lection of leeches. From 150,000 to 250,000 leeches are sometimes collected in one 
of the trips of the company’s steamer. They are then packed and conveyed to Mel¬ 
bourne, where a large proportion of them are put up for transmission abroad. 
Large numbers of them are sent to London and Paris, where, it is stated, they 
are preferred to leeches brought from any other place ; but the principal outlet 
for the export is America, where the demand is always great, from the absence 
or rarity of the proper kind of leech throughout the whole of that great conti¬ 
nent. The shipments of the company are made to San Francisco, Panama, and 
New York, whence they become distributed in all directions. The export from 
this colony appears likely to be a remunerative business for some years. The 
company referred to anticipates that from two to three millions of leeches will 
pass through their hands this season. 
