4. That he be kept from women and live not loosely with them; that he not so much as see or touch one; and that he guard himself from all impurity. Nothing weakens the understanding more than impurity. 5. That he know how to read and write well, and be also instructed in Latin, so far as to understand certain writings. 6. That such an one have sufficient means to devote himself without anxiety (to his art), and that his health be attended to with medicines when needful. C. The third part of the Prologue teacheth us of the great usefulness, joy, and delight which spring from painting. It falleth into six parts: 1. It is a useful art when it is of godly sort, and is employed for holy edification. 2. It is useful, and much evil is thereby avoided, if a man devote himself thereto who else had wasted his time. 3. It is useful when no one thinks so, for a man will have great joy if he occupy himself with that which is so rich in joys. 4. It is useful because a man gaineth great and lasting memory thereby if he applieth it aright. 5. It is useful because God is thereby honoured when it is seen that He hath bestowed such genius upon one of His creatures in whom is such art. All men will be gracious unto thee by reason of thine art. 6. The sixth use is that if thou art poor thou mayest by such art come unto great wealth and riches. II. The Second Division of the book treateth of Painting itself; it also is threefold. A. The first part is of the freedom of painting; in six ways. B. The second part is of the proportions of men and buildings, and what is needful for painting; in six ways.[90] 1. Of the proportions of men. 2. Of the proportions of horses. 3. Of the proportions of buildings. 4. Of perspective. 5. Of light and shade. 6. Of colours, how they are to be made to resemble nature. C. The third part is of all that a man conceives as subject for painting. III. The Third Division of the book is the Conclusion; it also hath three parts. A. The first part shows in what place such an artist should dwell to practise his art; in six ways. B. The second part shows how such a wonderful artist should charge highly for his art, and that no money is too much for it, seeing that it is divine and true; in six ways. The third part speaks of praise and thanksgiving which he should render unto God for His grace, and which others should render on his behalf; in six ways. III It is in the variety and completeness of his intentions that we perceive Dürer's kinship with the Renascence; he comprehends the whole of life in his idea of art training.