The primitive plough was hardly more than a pointed stout branch or stub of a tree, whose longer fork was fastened to the yoke. It made a furrow triangular in cross-section, broad at the top and narrowing to an edge at the bottom. It did not "turn" a strip, and between two furrows a long ridge was left unbroken. Even in Roman times cross-ploughing was common or usual. Even this rude culture needed the strength of cattle to draw the plough. The plough is associated in our minds with oxen, and the first man who made his cow, instead of his wife, draw the plough was a great benefactor. Even the domestication of cattle was less easy than it seems at first sight. Wild animals rarely reproduce in captivity. Pumpelly thinks that the way toward the domestication of our larger cattle may have been paved by a long period of drought driving them from the steppe into the better-watered oases, and thus into association with man. But this could hardly have been true of the mountain sheep and goats, on which man may well have experimented before he attempted the more difficult task of domesticating the larger, more powerful, and less manageable _Bos namadicus_. How did man hit upon the plan of castrating the bull and thus changing this intractable, ugly beast into the docile and patient ox? There seems to be a good amount of plausibility in Hehn's brilliant suggestion that this may have come about in connection with some ancient systems of religious rites and beliefs.[85] There is nothing impossible or very improbable in this view. But the very brilliancy of the conjecture and the clearness with which it is expressed, and the wealth of learning used to support it, warns us against too ready acceptance. We can only confess our complete ignorance and wait for future discoveries as patiently as we can. At present nearly all our knowledge of what was going on in this dim and remote past must be gained by a study of savages still holding the customs of the past in a somewhat or greatly modified form and spirit. Certain very general inferences may be made without great danger. But to frame clear and exact conceptions of life in these remote ages from these sources would demand a union of the boldest genius with the most wary caution. All these peoples have changed greatly during past millennia both for better and worse, usually probably in the latter direction. Customs have all been modified by changed conditions, surroundings, and inferences. It is exceedingly difficult to distinguish between what is really primitive and what is degenerate, perhaps of comparatively recent origin. The problem bristles with tantalizing questions, which tempt us to spin fascinating hypotheses all the more dangerous because of their attractiveness and apparent simplicity. Our great need is new facts and discoveries, and a clearer knowledge and understanding of old ones.