Abstract
The distribution of mast cells in muscle and liver of dystrophic mice was studied; histamine and histidine decarboxylase activity was also measured in the same tissues. Mast cells were significantly more numerous in dystrophic muscles. On the other hand, very few cells could be counted in the liver of either control or dystrophic animals. Histamine concentration was higher in muscle and liver of dystrophic mice; no visible increase in histidine decarboxylase activity could be measured by the methods used. It is concluded that histamine-binding capacity is increased in some tissues of dystrophic mice.