A family with diffuse partial woolly hair.

We report a family of six individuals with an abnormality of scalp hair characterized by shorter, finer, kinky hairs interspersed with normal hair, throughout the scalp. The abnormality had gone unnoticed in four of the six individuals. Two complained of thinning of the scalp hair.

Electron spin resonance spectrometrical study of the melanins in the wool of some North European sheep in relation to their color inheritance.

Additional peaks that were known on the esr-spectrograms of red human and reddish-brown Karakul hair to be diagnostic traits of phaeomelanin esr-signal also were found on esr-spectrograms of the tan, but not of black or chocolate brown wool from Icelandic sheep. This tan color is thought to depend on the presence of phaeomelanin and is due to the top dominant allele at the A locus. The two methods of distinguishing between eu- and phaeomelanin-dependent brown colors--esr-spectrometrical and genetical--are in agreement for European as well as for Asiatic breeds. Both light and dark brown Soay fleece samples lacked the additional peaks and are interpreted as eumelanin pigmentation.

Regeneration of wool follicles in autografts of sheep skin.

Three experiments involving six sheep were carried out at three different times in the annual wool growth cycle. Forty-eight full-thickness fitted autografts were sampled 2 h, 6 h, 24 h, 48 h, 3, 4, 5, 7, 9, 11, 14, 21 and 28 days after grafting. The histopathology of the grafts is described. Individual variation in 'take' was probably related to the speed with which vascular integrity was reestablished between graft and bed. Delayed acceptance caused the death of pilosebaceous units. In a successful graft, wool follicle regeneration appears to occur in three main ways: (1) an inactive follicle regenerates from the dormant bulb at about seven days, (2) follicles that were active at the time of grafting have first to form a papilla stalk, and such follicles did not become active until 11 days, (3) sometimes one or more outgrowths appeared at higher levels suggesting follicle regeneration by branching. In addition there were a few instances of de novo downgrowth of follicle plugs from the epidermis. Wool growth on the graft therefore arises almost entirely from the reorganisation of preexisting follicles.

Histological and histochemical studies of fetal skin follicles in Border disease of sheep.

The structure of the epidermis and dermis, and the distribution of reticulin, glycogen, lipid and sulphydryl groups in the skin have been examined in control and Border disease affected sheep fetuses at 95 and 115 days' gestation. In Border disease, there was a temporary retardation of development of the epidermis and skin follicles at 95 days. There was no difference in the structure of the dermis between control and experimental fetuses at either age. No evidence was found to suggest that the keratogenous process was abnormal in Border disease, but the sulphydryl zone of the primary fibres of affected fetuses was situated nearer the skin surface than in control fetuses. This may have been a consequence of the larger size of primary follices in Border disease. Glycogen present in the undifferentiated epidermis of both groups at 95 days' gestation was absent from the stratified squamous epithelium of the 115 days's fetuses. Glycogen and lipid droplets were present in the outer root sheath of primary follicles of all fetuses examined, but their significance is unknown.

Seasonal changes in the coat of the cat.

The coats of four cats were studied for 20 months through one winter and one summer in Australia. It was found that the outer coat and undercoat length varied from 25 mm and 12 mm in summer to 30 mm and 15 mm in winter. Follicle activity was at a maximum about February (late summer) and at a minimum in August (late winter). The peak of winter inactivity was narrow, and fell short of 100 per cent. During summer never more than 70 per cent of the outer coat hairs, and 50 per cent of the undercoat were active, indicating that despite a basic seasonal cycle, hair replacement is relatively gradual.