more to witness or to practise, except when necessary. Crossbreeding, however, is not necessary. I think that the prohibition to bring together two species in any kind of work, as included in the words, "Thou shalt not plow with an ox and an ass together" (Deut. xxii. 10), is only a preventive against the intercourse of two species. For if it were allowed to join such together in any work, we might sometimes also cause their intercourse. That this is the reason of the commandment is proved by the fact that it applies to other animals besides ox and ass; it is prohibited to plow not only with ox and ass together, but with any two kinds. But Scripture mentions as an instance that which is of regular occurrence.
As regards circumcision, I think that one of its objects is to limit sexual intercourse, and to weaken the organ of generation as far as possible, and thus cause man to be moderate. Some people believe that circumcision is to remove a defect in man's formation; but every one can easily reply: How can products of nature be deficient so as to require external completion, especially as the use of the fore-skin to that organ is evident. This commandment has not been enjoined as a complement to a deficient physical creation, but as a means for perfecting man's moral shortcomings. The bodily injury caused to that organ is exactly that which is desired; it does not interrupt any vital function, nor does it destroy the power of generation. Circumcision simply counteracts excessive lust; for there is no doubt that circumcision weakens the power of sexual excitement, and sometimes lessens the natural enjoyment: the organ necessarily becomes weak when it loses blood and is deprived of its covering from the beginning. Our Sages (Beresh. Rabba, c. 80) say distinctly: It is hard for a woman, with whom an uncircumcised had sexual intercourse, to separate from him. This is, as I believe, the best reason for the commandment concerning circumcision. And who was the first to perform this commandment? Abraham, our father! of whom it is well known how he feared sin; it is described by our Sages in reference to the words, "Behold, now I know that thou art a fair woman to look upon" (Gen. xii. 11).
There is, however, another important object in this commandment. It gives to all members of the same faith, i.e., to all believers in the Unity of God, a common bodily sign, so that it is impossible for any one that is a stranger, to say that he belongs to them. For sometimes people say so for the purpose of obtaining some advantage, or in order to make some attack upon the Jews. No one, however, should circumcise himself or his son for any other reason but pure faith; for circumcision is not like an incision on the leg, or a burning in the arm, but a very difficult operation. It is also a fact that there is much mutual love and assistance among people that are united by the same sign when they consider it as [the symbol of] a covenant. Circumcision is likewise the [symbol of the] covenant which Abraham made in connexion with the belief in God's Unity. So also every one that is circumcised enters the covenant of Abraham to believe in the unity of God, in accordance with the words of the Law, "To be a God unto thee, and to thy seed after thee" (Gen. xvii. 7). This purpose of the circumcision is as important as the first, and perhaps more important.
This law can only be kept and perpetuated in its perfection, if circumcision is performed when the child is very young, and this for three good reasons. First, if the operation were postponed till the boy had grown up, he
