2 28 A7iimal Life and Intelligence, 



This is the lying hid of characters and their subsequent 

 emergence. We may distinguish three forms of latency. 



1. Where characters lie hid till a certain period of life, 

 and then normally emerge. 



2. Where the characters normally lie hid throughout 

 life, but are, under certain circumstances, abnormally 

 developed. 



3. Where the characters lie hid throughout life, but 

 appear in the offspring or (sometimes distant) descendants. 



Latency is often closely connected with correlated 

 variations. Secondary sexual characters, for example, are 

 correlated with the functional maturity or activity of the 

 reproductive organs. They therefore lie hid until these 

 organs are mature and ready for activity. When they 

 are restricted to the male, they normally remain latent 

 throughout the life of the female, but reappear in her male 

 offspring. Under abnormal conditions, such as the removal 

 of the essentially male organs, the secondary sexual charac- 

 ters correlated with them do not appear, or appear in a 

 lessened and modified form. The males may even, under 

 such circumstances, acquire female characters. Thus 

 capons take to sitting, and will bring up young chickens. 

 Conversely, females which have lost their ovaries through 

 disease or from other causes sometimes acquire secondary 

 sexual characters proper to the male. Characters thus 

 normally latent abnormally emerge. Mr. Bland Sutton* 

 gives a case of a hen golden pheasant which "presented 

 the resplendent dress of the cock, but her plumage was not 

 quite so brilliant ; she had no spurs, and the iris was not 

 encircled by the ring of white so conspicuous in the male." 

 Her ovary was no larger than a split pea. 



A curious instance of latent characters correlated with 

 sex is seen in hive bees. The worker bee differs from the 

 female in the rudimentary condition of the sexual organs, 

 in size and form, and in the higher development of the 

 sense-organs. But it is well known that, if a very young 

 worker grub be fed on " royal jelly," she will develop into 



* " Evolution and Disease," p. 169. 



