The Influence of Genetic Constitution 



an atypical mechanism of sex-determination, evidence is in- 

 adequate, but Bellamy (1934) found no conspicuous sex differ- 

 ence in longevity in a small series. An example of longer life in 

 the male teleost occurs in minnows (van Cleave and Markus, 

 1929) but this refers to a wild population. It seems altogether 

 likely that where a sex difference in longevity is observed it 

 arises from the sum of differences in metabolic rate and be- 

 havioural pattern — in other words, from physiological sexual 

 dimorphism. A number of invertebrate metabolic studies sup- 

 port such a view (Daphnia, Mc Arthur and Baillie, 1929a, b; 

 Drosophila, Alpatov and Pearl, 1929), by indicating that the 

 'rate of living' in the male is in fact higher. The degree to 

 which the inferior vitality of the male mammal results directly 

 from the action of androgens has been discussed, and the whole 

 question of male mortality reviewed at length, by Hamilton 

 (1948). In man, the higher male mortality is present both in 

 utero and in infancy. At later ages the question is, of course, 

 complicated by social and occupational factors (Herdan, 1952). 

 There are as yet no fully satisfactory human data upon the 

 relative longevity of castrates, though their life-span is certainly 

 not grossly inferior to that of normals. Many of the highest 

 recorded ages in cats have occurred in gelt males (p. 48) . The 

 finding of Slonaker (1930) that castration produces a slight 

 decrease in rat longevity was based on too few animals to be 

 significant. 



In some instances (Drosophila, Bilewicz, 1953) the life of the 

 male is still further shortened by copulation. In others (Latro- 

 dectes, Shulov, 1939-40) the male dies after a determinate short 

 life-span, whether mated or not. While the mortality of Anglican 

 clergy in England during the 1930's was only 69 per cent of 

 the general male mortality, and that of other Protestant clergy 

 74 per cent, the mortality of Roman Catholic clergy was 105 per 

 cent (Registrar-General's statistics, 1938). This observation is 

 complicated by a variety of factors: in rats, however, regular 

 mating improves the condition and longevity of the male 

 (Agduhr, 1939; Agduhr and Barron, 1938). This might tend 

 to support the view that the virtues of 'continence' in man, 

 vis-a-vis longevity, have been over-praised by interested parties. 

 After citing the opinion given by the Dutch physician Boerhave 



133 



