1. Clear, filtered glycerol extracts of chopped liver, spleen, and kidney contain an ester-splitting ferment.
2. The esterase content of extracts of the liver and spleen of normal dogs is reasonably constant.
3. The amount of esterase in the liver does not appear to vary to any great extent from the normal, in poisoning with chloroform and phosphorus.
4. Feeding large quantities of sugar and increasing the amount of glycogen in the liver is accompanied by a marked increase in the esterase content of that organ. This increase is also evident in phosphorus-poisoned animals which have been fed large amounts of sugar.
5. The feeding of sugar does not prevent the increase in esterase in the blood serum of animals poisoned with phosphorus.
6. The esterolytic power of extracts of the kidney varies considerably in different dogs.