These problems have dealt with the mechanical or operational processes. However, there are other problems dealing with the completing of the descriptive information. The fingerprint card may be returned because of the lack of information in the spaces provided, such as name, sex, race, height, weight, etc. Any discrepancies in this information may necessitate the return of the fingerprint card. The success and value of the FBI's fingerprint files to all law enforcement agencies are dependent, in a large measure, on the legibly inked fingerprints taken by law enforcement agencies. Figure 386 shows an enlarged portion of the bulb of a finger revealing the microscopic structure of the friction skin. The epidermis consists of two main layers, namely, the stratum corneum, which covers the surface, and the stratum mucosum, which is just beneath the covering surface. The stratum mucosum is folded under the surface so as to form ridges which will run lengthwise and correspond to the surface ridges. However, these are twice as numerous since the deeper ridges which correspond to the middle of the surface ridges alternate with smaller ones which correspond to the furrows. The sweat pores run in single rows along the ridges and communicate through the sweat ducts with the coil sweat glands which are below the entire epidermis. The friction ridges result from the fusion in rows of separate epidermic elements, such as the dot shown on the left. Generally speaking, when an individual bruises or slightly cuts the outer layer or stratum corneum of the bulb of the finger, the ridges will not be permanently defaced. However, if a more serious injury is inflicted on the bulb of the finger, thereby damaging the stratum mucosum, the friction skin will heal, but not in its original formation. The serious injury will result in a permanent scar appearing on the bulb of the finger. [Illustration: 386] CHAPTER X _Problems and Practices in Fingerprinting the Dead_ Each year new graves are opened in potter's fields all over the United States. Into many of them are placed the unknown dead--those who have lived anonymously or who, through accident or otherwise, lose their lives under such circumstances that identification seems impossible. In a majority of such cases, after the burial of the body, no single item or clue remains to effect subsequent identification. As a result, active investigation usually ceases and the cases are forgotten, unless, of course, it is definitely established that a murder has been committed.