functions of the presexual stage are found to be permanently suitable, and, therefore, are retained later on as sexual functions. Thus, for example, the mouth zone is retained as of erotic importance, meaning that its valuation is permanently fixed. Concerning the mouth, we know that it also has a sexual meaning among animals, inasmuch as, for example, stallions bite mares in the sexual act; also, cats, cocks, etc. A second significance of the mouth is as an instrument of speech, it serves essentially in the production of the mating call, which mostly represents the developed tones of the animal kingdom. As to the hand, we know that it has the important significance of the contrectation organ (for example, among frogs). The frequent erotic use of the hand among monkeys is well known. If there exists a resistance against the real sexuality, then the accumulated libido is most likely to cause a hyperfunction of those collaterals which are most adapted to compensate for the resistance, that is to say, the nearest functions which serve for the introduction of the act;[317] on one side the function of the hand, on the other that of the mouth. The sexual act, however, against which the opposition is directed is replaced by a similar act of the presexual stage, the classic case being either finger-sucking or boring. Just as among apes the foot can on occasions take the place of the hand, so the child is often uncertain in the choice of the object to suck, and puts the big toe in the mouth instead of the finger. This last movement belongs to a Hindoo rite, only the big toe was not put in the mouth, but held against the eye.[318] Through the sexual significance of the hand and mouth these organs, which in the presexual stage served to obtain pleasure, are invested with a procreating power which is identical with the above-mentioned destination, which aims at the external object, because it concerns the sexual or creating libido. When, through the actual preparation of fire, the sexual character of the libido employed in that is fulfilled, then the mouth zone remains without adequate expression; only the hand has now reached its real, purely human goal in its first art. The mouth has, as we saw, a further important function, which has just as much sexual relation to the object as the hand, that is to say, the production of the mating call. In opening up the autoerotic ring (hand-mouth),[319] where the phallic hand became the fire-producing tool, the libido which was directed to the mouth zone was obliged to seek another path of functioning, which naturally was found in the already existing love call. The excess of libido entering here must have had the usual results, namely, the stimulation of the newly possessed function; hence an elaboration of the mating call.