It may be congenital or acquired, and maybe limited to a small or large area, or develop simultaneously at several regions. All parts of the skin, including the follicles, glands and subcutaneous connective and areolar tissue, share in the hypertrophy; and this in exceptional instances may be so extensive that the integument hangs in folds. The enlargement of the follicles, natural folds and rugae gives rise to an uneven surface, but the skin remains soft and pliable. There is also increased pigmentation, the integument becoming more or less brownish. #What course does dermatolysis pursue?# Its development is slow and usually progressive. It gives rise to no further inconvenience than its weight and consequent discomfort. #Give the etiology.# The etiology is obscure. It is considered by some authors as allied to molluscum fibrosum, and, in fact, as a manifestation of that disease, ordinary molluscum tumors sometimes being associated with it. It is not malignant. #What is the pathology?# The disease consists of a simple hypertrophy of all the skin structures and the subcutaneous connective tissue. #What is the treatment of dermatolysis?# Excision when advisable and practicable. #CLASS V.--ATROPHIES.# #Albinismus.# #What do you understand by albinismus?# Congenital absence, either partial or complete, of the pigment normally present in the skin, hair and eyes. #Describe complete albinismus.# In complete albinismus the skin of the entire body is white, the hair very fine, soft and white or whitish-yellow in color, the irides are colorless or light blue, and the pupils, owing to the absence of pigment in the choroid, are red; this absence of pigment in the eyes gives rise to photophobia and nystagmus. _Albinos_--a term applied to such individuals--are commonly of feeble constitution, and may exhibit imperfect mental development. #Describe partial albinismus.# Partial albinismus is met with most frequently in the colored race. In this form of the affection the pigment is absent in one, several or more variously-sized patches; usually the hairs growing thereon are likewise colorless. #Is there any structural change in the skin?# No. The functions of the skin are performed in a perfectly natural manner, and microscopical examination shows no departure from normal structure save the complete absence of pigment. #What is known in regard to the etiology?# Nothing is known of the causes producing albinismus beyond the single fact that it is frequently hereditary. #Does albinismus admit of treatment?# No; the condition is without remedy. #Vitiligo.# (_Synonyms:_ Leucoderma; Leucopathia.) #Give a definition of vitiligo.# Vitiligo may be defined as a disease involving the pigment of the skin alone, characterized by several or more progressive, milky-white patches surrounded by increased pigmentation. #Describe the symptoms of vitiligo.#