DIGESTION OF FAT IN AMOEBA PROTEUS

¹ From the Marine Biological Laboratory, Woods Hole, and the Zoölogical Laboratory, Johns Hopkins University

1. If a colpidium which contains numerous globules of fat is ingested by an amoeba which contains no fat, the food vacuole and its content soon divide several times forming a number of vacuoles, each containing a fragment of the colpidium.

2. The globules of fat in these fragments gradually disappear and as they disappear, small droplets of fat appear in the cytoplasm of the amoeba, which gradually increase in size and number until in 24 hours all the fat in the fragments has disappeared and the cytoplasm of the amoeba is well filled with globules of it.

3. Treatment with Nile blue sulfate shows that the fat in the intact colpidia and that in the cytoplasm of the amoebae is neutral, but that the fragments of colpidia in the food vacuoles contain fatty acid as well as neutral fat.

4. The fact that the globules of fat in the fragments of colpidia in the food vacuoles are much smaller than those in the cytoplasm of the amoebae when first observed, shows that they do not pass out into the cytoplasm and it indicates that the fat is digested in the fragments and passes out in solution. The fact that fatty acid is formed in the fragments indicates that the fat in them is split into fatty acid and glycerine which pass out into the cytoplasm and unite there to form neutral fat.