Studies on Animal Lactase

Summary. On the basis of determinations of lactase activity performed on human foetuses, cows and rabbits of different age it is possible to establish that the ventricle, colon and pancreas do not contain any lactase. Bile from calves is free from lactase. The experiments on human foetuses show that there is lactase in the wall of the small intestine from the 5th month of intrauterine life. The activity is found to rise with increasing intrauterine life. In cows and rabbits the lactase activity in the mucous membrane of the small intestine is largest in quite young animals. The amount decreases in distal direction of the small intestine and with increasing age. Continued administration of lactose to the food until 15 weeks after birth is unable to preserve the lactase activity in the mucous membrane of the small intestine from rabbits.