_Uric_, or _lithic acid calculi_, are the most frequent in their presence. They may vary in size, from a pea to that of a hen’s egg. In color, also, they may vary from a fawn or light yellow, to a dark, almost mahogany tint. The surface may be slightly tuberculated, or smooth, and the interior, where a section is made, has a concentric arrangement of layers around a central nucleus. _Oxalate of lime calculi_ are next in frequency. From the strongly tuberculated character of the surface, they are frequently known as mulberry calculi. They are of an irregular, spherical form, and usually single. In color, they are usually of a dark olive or brown, but may be light and almost white. They seldom acquire so large a size as the lithic acid variety, are very hard, and permit of a high polish. _Phosphatic calculi_ are characterized by their softness, which permits of their being readily crushed. They are of a grayish-white color, and frequently composed of alternate layers of other deposits. They may be composed wholly of phosphate of lime, or of a triple phosphate—ammonio-magnesian phosphate—or of a combination of the two. _Cystine calculi_ are very rare; they are yellowish in color, of a waxy appearance, and soluble in aqua-ammonia. _Uric oxide calculi_ are extremely rare; they resemble uric acid calculi, but present a waxy appearance when polished. CHAPTER III. THE MALE GENERATIVE ORGANS. Section I. OF THE PENIS. [=Notice=: Malformations; size; condition of prepuce and glans; chancres, warts, etc. Split open urethra and notice ulcers, strictures, etc.] =Congenital Anomalies.= The penis may be very imperfectly developed, even with a normal development of the other organs of generation, although it more frequently occurs when the latter are themselves imperfect. It occasionally happens that, from an arrest of union in the median line of the penis, a slit or fissure is left communicating with the urethra. This commonly occurs in the under surface, constituting _Hypospadias_; less frequently on the upper surface, (_Epispadias_,) and only in cases of extroversion of the bladder. The prepuce may be wanting. Congenital phymosis occasionally occurs, usually associated with atrophy of the penis. It is supposed by some, to be a predisposing cause of cancer of the penis. =Hypertrophy and Atrophy.= In consequence of long-continued onanism, the penis may become hypertrophied, or as the result of chronic irritation and disease, we may have an hypertrophy of the prepuce and of the body of the penis, sometimes attaining an enormous size. Vidal has related and figured a case where the organ reached to below the knees, and was as large as a thigh. Atrophy of the penis, accompanied with obliteration of the cavernous textures, occurs with atrophy of the testicles.