OF EXPERIMENTAL WORK I 53 



Recovery from Anaesthetics. — Unfertilized eggs may be kept two hours in optimum 

 concentration of anyurethane listed inTable 14 and recover in sea water immediately ; 

 fertilized eggs undergo slight development while in urethane and time of first 

 cleavage on recovery is independent of duration of exposure, 40 minutes to two 

 hours in ethyl urethane (E. B. H., 1930 unpub.). Similar results for alcohols (Blumen- 

 thal, 1928). 



Differential susceptibility and recovery (with ethyl alcohol) with relation to axial 

 gradients (Child, 1916a, b). 



Acceleration of cleavage on return of anaesthetised eggs to sea water (Blumenthal, 

 1928). 



Prolongation of Life. — Of unfertilized egg. By chloral hydrate (Loeb, 1913a, p. 91). 

 With 2 % ethyl alcohol, life is doubled, and this is not due to bactericidal action 

 (Tyler, Ricci, and Horowitz, 1938). See also under Cyanides. 



Salts and Anaesthetics. — Antagonism (R. S. Lillie, 1912, 1914a, 1917). 

 Effect of Temperature. — On carbamate narcosis (Cornman, 1950 b). 

 Respiration and Cleavage. — Anaesthetics prevent cleavage with little effect on re- 

 spiration. See Respiration A III i. First shown by Warburg (1910) for Paracen- 

 trotus lividus with phenyl urethane; 0.0005 M phenyl urethane blocks cleavage and 

 reduces oxygen consumption to 80 % of normal. More fully studied in S. purpuratus 

 with ethyl urethane and other anaesthetics by Loeb and Wasteneys (1913b). In 

 Arbacia, 0.00 1 M phenyl urethane blocks cleavage and reduces oxygen consumption 

 to 70 % of control (Clowes and Krahl, 1940, Krahl and Clowes, 1940). o.i M ethyl 

 urethane stops cleavage and reduces oxygen consumption to 75 % (Fisher and Henry, 

 1944, Fisher, Henry, and Low, 1944). 0.0045 ^ chloral hydrate blocks cleavage, 

 leaving 45 % oxygen consumption, (and has practically no effect on unfertilized 

 eggs) (Fisher and Henry, 1944). See Table VIII of Krahl (1950). For barbiturates 

 and local anaesthetics (benzoates, etc.) on cleavage and oxygen consumption see 

 Clowes and Krahl (1940); Krahl and Clowes (1940); Clowes Keltch and Krahl 

 (1940) ; Krahl, Keltch and Clowes (1940 a) ; see Tables VI and VII of Krahl (1950). 

 For urethane and methylene blue on respiration (Barron, 1929). 



Permeability. — Decreased by anaesthetics (R. S. Lillie, 1912, 1914a, b, 1916c, 

 1918b, etc.; Luckeand McCutcheon, i932,but see 1926 a and Lucke, 1931). Increase 

 due to fertilization is prevented by anaesthetics (R. S. Lillie, 1918a, b; Lucke and 

 McCutcheon, 1932. For Table of concentrations effective in preventing increase 

 of permeability, which are similar to those arresting cleavage see R. S. Lillie (1918b, 

 p. 426). According to Heilbrunn (1925c, 1943, pp. 144, 531), permeability is not 

 decreased by ether. According to McClendon (1909 b) permeability is increased by 

 all agents causing parthenogenesis, including ether. 



Viscosity. — Decreased if anaesthetic is dilute, increased if concentrated (Heilbrunn, 

 1920a, b, 1925c, 1927, 1928, p. 205; by centrifuge tests). See Table 15 from Heil- 

 brunn (1928) giving concentrations and lethal doses of many anaesthetics, with 

 regard to viscosity. Decrease in 2.5 % ether according to Heilbrunn (1920a), increase 

 according to Chambers (1924, p. 250); but Heilbrunn (1925c, p. 474 and 1928, 

 p. 207) thinks Chambers' results were due to heating by microscope lamp. Decrease 

 in 0.2 M ethyl urethane by centrifuge tests (E. B. H., 1930 unpub.). Chloretone 

 increases viscosity (Heilbrunn, 1920 a, b). 



Parthenogenesis. — Caused by chloroform, ether, alcohol (Mathews, 1900; McClen- 

 don, 1909b, 1910b; Heilbrunn, 1928, p. 261). By acetone, chloretone, urethane, 

 chloral hydrate, methyl acetate, ethyl acetate, ethyl butyrate, methyl salicylate 

 (Heilbrunn, 1913; Just, 1929a for acetone). Parthenogenesis by hypertonic sea 

 water prevented by anaesthetics (R. S. Lillie, 1914a, b, 191 7; Heilbrunn, 1920a). 

 Reversal of parthenogenesis with chloral hydrate (or NaCN) ; (Loeb, 1913 c, 1914b, 

 1915 b); this is denied by F. R. Lillie and Just (1924, p. 505). See Cyanides. 

 Sperm Respiration. — Ethyl urethane, o. i M increases respiration by 23 % ; 0.0 1 M 



