Quantitative estimation of lipid in the fore-, mid-, hind brain and the spinal cord of chick at various stages of development from 4- to 20-days of incubation has been made. 2. It is observed that lipid concentration increases in the period of 4- to 8-days of incubation but becomes diminished in 10- to 12-day embryos. 3. There is a rise in quantity of lipids in most of the regions of the central nervous system in 15- to 20-days' embryos. 4. The findings have been discussed in relation with differentiation of the central nervous system of chick.
