Now here we seem to find want of social structure and want of law going together as cause and effect. The "friends" of whom we hear need to be organized into a police force. If we now turn to totemic society, with its elaborate clan-system, it is quite another story. Blood-revenge ranks amongst the foremost of the clansman's social obligations. Over the whole world it stands out by itself as the type of all that law means for the savage. Within the clan, indeed, the maxim of blood for blood does not hold; though there may be another kind of punitive law put into force by the totemites against an erring brother, as, for instance, if they slay one of their number for disregarding the exogamic rule and consorting with a woman who is all-one-flesh with him. But, between clans of the same tribe, the system of blood-revenge requires strict reprisals, according to the principle that some one on the other side, though not necessarily the actual murderer, must die the death. This is known as the principle of collective responsibility; and one of the most interesting problems relating to the evolution of early law is to work out how individual responsibility gradually develops out of collective, until at length, even as each man does, so likewise he suffers. The collective method of settling one's grievances is natural enough, when men are united into groups bound together by the closest of sentimental ties, and on the other hand there is no central and impartial authority to arbitrate between the parties. One of our crew has been killed by one of your crew. So a stand-up fight takes place. Of course we should like to get at the right man if we could; but, failing that, we are out to kill some one in return, just to teach your crew a lesson. Comparatively early in the day, however, it strikes the savage mind that there are degrees of responsibility. For instance, some one has to call the avenging party together, and to lead it. He will tend to be a real blood-relation, son, father, or brother. Thus he stands out as champion, whilst the rest are in the position of mere seconds. Correspondingly, the other side will tend to thrust forward the actual offender into the office of counter-champion. There is direct evidence to show that, amongst Australians, Eskimo, and so on, whole groups at one time met in battle, but later on were represented by chosen individuals, in the persons of those who were principals in the affair. Thus we arrive at the duel. The transition is seen in such a custom as that of the Port Lincoln black-fellows. The brother of the murdered man must engage the murderer; but any one on either side who might care to join in the fray was at liberty to do so. Hence it is but a step to the formal duel, as found, for instance, amongst the Apaches of North America.