犬

Histological and cytological observations have been undertaken to investigate the structure and function of the apocrine sweat gland in the dog. The results obtained are as follows; 1) Many apocrine sweat glands are found in any parts of hairy skin in the dog. From the developmental stages of these secretory tubules we classified them into three types, namely, type I, II and III. The first one has a primitive club shaped secretory tubule, the second one has a tortuous undulating tubule and the last one has a glomerular tubule. 2) From the point of the functional phases of the gland we divided them into three stages, namely, secreting, resting and accumulating stages. They may be supposed to change each other in one functional cycle. 3) There are two types of secretion in secretory cells. One is the typical apocrine secretion, and the other resembles to the eccrine type. 4) Secretory cells of apocrine sweat glands contain a large amount of neutral mucopolysaccharides or mucoproteins, and also contain lipid droplets. 5) Ductal part of the gland of the dog is structurally identical with man’s. But, the former is smaller and shorter than the latter. Moreover, cuticular border of the surface epithelium of the duct is poorly developed in the dog. 6) Modified glands transformed from the apocrine sweat glands are found in the circumanal region. Histological and cytological structure of these glands are identical with the circumanal glands observed in the cow and man. It may be supposed that these glands are intermediate type between the apocrine and eccrine sweat glands.