OF EXPERIMENTAL WORK 165 



translation, p. 403, see above under Acceleration. Inhibition reversed by adenosine 

 triphosphate, ATP (Barnett, 1953). 



Parthenogenetic Treatment. — Delay; first cleavage (at 23° C.) occurs i^ to 5 hours 

 after activaticn; fertilized eggs cleave 50 minutes after fertilization (E. B. Harvey, 

 1936, 1951 ; E. B. Harvey and Hollaender, 1938). Delay also noted by Loeb (1900 a, 

 1904; Moser (1940) and others. For general information about Arbacia and other 

 species see Loeb's Artificial Parthenogenesis (1913a). 



Penicillin and Penichromin. — (Henry and Henry, 1945; Cornman, 1949). Slight in- 

 hibition of cleavage with very weak concentrations of noncrystalline samples of 

 penicillin, but virtually no effect with highly purified samples (Clowes and Keltch, 

 1946 unpub., per Krahl, 1950, p. 206). 



Perivisceral Fluid. — (F. R. Lillie, 1913 a, 19 14, 19 19, p. 173; A. E. Woodward, 

 1 9 18; Just, 1922a, HI; Goldforb, 1935b). 



pH. — Delay of cleavage below pH 6.0 and above 9.4; acceleration pH 8.2 to 9.2 

 (Clowes and Smith, 1923; Smith and Clowes, 1924b, c, d). See under Acid and 

 Alkali above and under Alkali in Cleavage: Acceleration. 



Phenols, Cresols and Related Substances. — (Clowes and co-workers, 1 934-1 951, 

 especially Clowes and Krahl, 1936a; Krahl and Clowes, 1936a, 1938; Clowes 195 1). 

 See the comprehensive review of Krahl (1950, p. 196 and his Tables HI, IV). 

 Also Waterman (1938, 1941) ; Villee, Lowens et al. (1949) ; A. Scott (1950). Incom- 

 plete reversal of inhibition of dinitrophenol by ATP (Barnett, 1953). For Dendraster 

 excentricus see Pease (1941). 



Phosphorus, P^^. — (Green and Roth, 1950). 



Pilocarpine. — In high concentrations, delay; in low concentrations accelerate 

 cleavage (Mathews, 1901 a; Sollman, 1904a; Balzer and Villee, 1951, but see Villee 

 and Villee, 1952). For Dendraster excentricus see Rulon (1941 b) ; Pease (1942 b). 



Podophyllin, Podophyllotoxin, Quercitin and Derivatives. — -(Cornman, 1947 a; Cornman 

 and Cornman, 1951). 



Polysaccharides. — Heparin, etc. (C. V. Harding, 195 1). 



Pressure, Hydrostatic. — (Marsland, 1938, 1950, 1951; Kitching and Moser, 1940; 

 E. B. H., 1933 unpub.). For Arbacia lixula see Marsland (1939). 



''Purple X" — (Glaser, 1914c; A. E. Woodward, 1915, 1918). 



Pyocyanine. — (Runnstrom, 1935 a; Clowes and Krahl, 1936 a; Krahl, 1950, Table 

 VIII; Waterman, 1938, 1941). For Dendraster excentricus see Pease (1942b); Moore, 

 Bliss, and Anderson (1945) also for S. purpuratus. 



Quinine. — Very poisonous ; one part of quinine sulphate in 1 7,000 parts sea water 

 stops cleavage (Mathews, 1907). Poisonous action noted by O. and R. Hertwig in 

 1887. 



Radium. — Beta rays delay, alpha rays accelerate cleavage (Packard, 191 5, 19 16). 



"Red Tide." — Dinoflagellate-contaminated sea water. (Cornman, 1947b). 



Rhodamine B and Light. — (L. B. Clark, 1940). 



Rotenone. — And related compounds (Cornman and Rogers, 1951; Rogers and 

 Cornman, 195 1). 



Season. — Cleavage delay late in the season (Medes, 191 7; Woodward, 19 18; Fry, 

 1936; E. B. Harvey, 1939 b). 



Sperm Extracts. — (Frank, 1939). 



Sugar. — (R. S. Lillie, 1903; Loeb, 1913 a, p. 130 for Strongylocentrotus purpuratus 

 with good discussion of sugar effects; R. S. Lillie and Cattell, 1923). No fertilization 

 in isotonic sugar solution, but cleavage when returned to sea water even after 5 

 hours in sugar (E. B. Harvey, 1932). 



Sulfide, Sodium. — (Krahl, Keltch, Neubeck, and Clowes, 1941; Krahl, 1950, 



P- 195)- 



Sulphanilamide. — And related compounds (Fisher, Henry, and Low, 1944; Krahl, 

 1950, Table VIII). 



