The glucuronide-synthesizing system in the mouse and its relationship to β-glucuronidase

puppy but would not appear to be essential since the three puppies reared on evaporated cow's milk throve satisfactorily without it.Apart from this, however, bitches' colostrum should provide a valuable source of unspecific cholinesterase in high concentration, and it is hoped to investigate some of the problems arising out of the ob- servations here presented.SUMMARY 1.In newborn humans, rats, rabbits and cats the cholinesterase activity of the serum tended to be near the adult level and to rise soon afterwards to about twice the initial value.In guinea pigs the activity did not rise.2. The colostrum of man and of the cat had negligible cholinesterase activity.3. In puppies the serum cholinesterase rose to 25 times its birth level in 3 days.This increase appears to be due to the very high cholinesterase activity of bitches' colostrum.The human material was obtained from the Landes- frauenklinik, Wuppertal, through the courtesy of the Director, Prof. Anselmino.A pure-bred setter was obtained from Mr Parry, the Canine Research Station, Kennet.