Up to this point we have been necessarily supposing that the capitalist succeeds in making a profit. But, as we know, it often happens that he does not attain his end, that his capital produces no added value, that he even loses it entirely or in part. This case being important for the subject in hand we must stop to consider it for a moment. As has been shown above, the capitalist begins by purchasing labor and the means of production in order to set in motion the process of production. For him the difficulty then consists of selling the manufactured product at its value and of thus realizing the added value which is a part of this. At times, aided by circumstances, he succeeds in selling the product above its value, and so makes an extra profit. On the other hand, he runs the risk of having to sell the product below its value, or of not being able to sell it at all. The causes of the poor success of the process are of different kinds. In the first place, the capitalist may not have the ability necessary for the direction of the process of production. For example, the product made under his management may be inferior to that of his competitor, though the cost of production is the same; the means of production may be purchased at too high a price; he may not have been in touch with the tastes of consumers, etc.; reasons all of which render his product unsalable, or salable at a loss. In the second place, circumstances independent of his own act may present themselves which have the same result. Let us look at some of them. To begin with, the unforeseen cessation of payment on the part of one of his important debtors may oblige him to sell his goods at a sacrifice in order to satisfy his creditors. Again, he may lack the capital necessary to meet competition. For the amount of capital necessary in every branch of industry or commerce becomes greater and greater, and the man who cannot procure this capital is forced little by little to give ground to his competitors and finally to give up business altogether. In the third place, it very often happens that, as a result of competition, there is an oversupply of commodities, which from this very fact are unsalable, or must be sold for less than their value. In the periods of prosperity this case is not general. But it is the rule in crises. Because of their great importance to the relation between criminality and economic conditions, it is necessary to pause here to examine the cause and origin of these crises. Economic crises, that is to say periods in which the economic life is greatly disturbed, are due to various circumstances; for example, to a war which puts obstacles in the way of the regular continuance of international commerce. But aside from such causes there are others which are natural to the present economic system itself, and which bring on these crises periodically. It is these causes, which are the more important, of which it is necessary to treat here.