OF EXPERIMENTAL WORK 1 95 



tracted from sperm nucleic acid (Daly, Allfrey and Mirsky, 1950). From sperm and 

 eggs, but no uracil in sperm, no thymine in eggs (Marshak and Vogel, 195 1). 

 Synthesis of nucleic acid purines, adenine and guanine (Abrams, 1951). See Marshak 

 and Marshak, 1953. 



Effect of Various Drugs. — On nucleic acid metabolism (Villee, et al., 1949; Villee 

 and Villee, 1952). Inhibition of DNA and DNase by usnic acid (Marshak and 

 Fager, 1950). 



Other Species (additional) and General References 



Bernstein and Mazia, 1953 a, b. S. purpuralus. 



Brachet, 1947, 1952. General. 



Brachet, 1950. Chemical Embryology, Chapt. 6, general. 



Callan, 1949. Naples species, RNA in eggs. 



Ca.person and Schultz, 1940. Psammechinus miliaris, ultraviolet. 



Elson and Chargaff, 1 952 a, b. Paracentrotus lividus, DNA in eggs and sperm ; PNA in embryos. 



Hultin, 1949a. A. lixula, Ps. miliaris etc., agglutination by nucleoproteins. 



Krahl, 1950. Review, p. 187. 



Lison and Pasteels, 1951. P. lividus, amount DNA at different stages. 



Loeb, 1907. Nuclein synthesis, general. 



Masing, 1910. A. lixula, no nuclein synthesis in development. 



Mirsky and Ris, 1951. Echinometra and general. 



Needham and Needham, 1930. Dendraster excentricus, nuclein synthesis. 



Rothschild, 1951a. Purines and pyrimidines in sperm oi Echinus esculentus. 



Runnstrom, 1952. General, in Barron's Modern Trends. 



Symposium on nucleic acids, 1947. Cold Spring Harbor Symposia, vol. 12. 



Symposium on nucleic acid, 1947. Symposia of Society for Experimental Biology, no. i. 



Symposium (Discussion) on nucleic acids, 1951. J. Cell, and Comp. Physiol. 38, supplement 



no. I. 

 Vendreley, C. and R., 1949. A. lixula, P. lividus. 



OIL 



See also Lipids 



Size. — Of oil globules in egg. Diameter 0.6-1.0 \j. (E. B. H. per E, N. Harvey, 1932 a; 

 E. B. Harvey, 1936). Smaller than i jjl (Chambers, 1938 a); et al. 



Density. — Lightest material in egg; goes to centripetal pole in centrifuged eggs, 

 forming an oil cap (Lyon, 1906a, 1907); McClendon, 1909a; E. B. Harvey, 1932, 

 1936, etc.; et al.). 



Amount. — Of oil in oil cap. i % of egg (E. N. Harvey, 1932a) ; 2 % (Costello, 1939). 

 In Lytechinus variegatus there is usually no oil cap but sometimes a few oil drops at 

 centripetal pole; good oil cap in dilute (80 %) sea water (E. B. H.). 



Decrease. — In number of oil drops (in sections) from unfertilized egg to 4-cell stage, 

 slight increase in blastula (Pelluet, 1938). 



Stain. — Oil cap does not stain with any vital dyes tried (E. B. Harvey, 1941 c). In 

 fixed preparations; oil cap does not blacken much with osmic acid and does not 

 stain (Lyon, 1907). Black with osmic acid, subsequently bleaches with turpentine; 

 black with Benda-Kuhl (E. B. Wilson, 1926); cf. Pelluet (1938). Oil cap does not 

 show in preparations fixed in Bouin but does after formalin and Flemming (E. B. 

 Harvey, 1940 c; E. B. Harvey and Lavin, 1944). 



Ultraviolet Light. — Oil cap is slightly absorbing (E. B. Harvey and Lavin, 1944). 



Effect of Ammonium Salts. — "Lipophanerosis" (see Needham, 1942, p. 206), in- 

 crease in size of oil cap, probably due to release of bound oil (Heilbrunn, 1936; 

 Wiercinski, 1944; cf Kopac (1948 a) ; see also Navez 1938; Navez and Du Bois, 1940; 



