The right of inheritance, against which so much has been objected of late, is one of the forms of gift, and assuredly the most natural of all.  That which a man has produced, he may consume, exchange, or give.  What can be more natural than that he should give it to his children?  It is this power, more than any other, which inspires him with courage to labour and to save.  Do you know why the principle of right of inheritance is thus called in question?  Because it is imagined that the property thus transmitted is plundered from the masses.  This is a fatal error.  Political economy demonstrates, in the most peremptory manner, that all value produced is a creation which does no harm to any person whatever.  For that reason it may be consumed, and, still more, transmitted, without hurting any one; but I shall not pursue these reflections, which do not belong to the subject.

Exchange is the principal department of political economy, because it is by far the most frequent method of transmitting property, according to the free and voluntary agreements of the laws and effects of which this science treats.

Properly speaking, exchange is the reciprocity of services.  The parties say between themselves, “Give me this, and I will give you that;” or, “Do this for me, and I will do that for you.”  It is well to remark (for this will throw a new light on the notion of value) that the second form is always implied in the first.  When it is said, “Do this for me, and I will do that for you,” an exchange of service for service is proposed.  Again, when it is said, “Give me this, and I will give you that,” it is the same as saying, “I yield to you what I have done, yield to me what you have done.”  The labour is past, instead of present; but the exchange is not the less governed by the comparative valuation of the two services:  so that it is quite correct to say that the principle of value is in the services rendered and received on account of the productions exchanged, rather than in the productions themselves.

In reality, services are scarcely ever exchanged directly.  There is a medium, which is termed money.  Paul has completed a coat, for which he wishes to receive a little bread, a little wine, a little oil, a visit from a doctor, a ticket for the play, &c.  The exchange cannot be effected in kind, so what does Paul do?  He first exchanges his coat for some money, which is called sale; then he exchanges this money again for the things which he wants, which is called purchase; and now, only, has the reciprocity of services completed its circuit; now, only, the labour and the compensation are balanced in the same individual,—­“I have done this for society, it has done that for me.”  In a word, it is only now that the exchange is actually accomplished.  Thus, nothing can be more correct than this observation of J. B. Say:—­“Since the introduction of money, every exchange is resolved into two elements, sale and purchase.  It is the reunion of these two elements which renders the exchange complete.”