1224 LIFE : OUTLINES OF GENERAL BIOLOGY 



daily tiredness, from which more or less complete recuperation is 

 provided by rest (including meals); (2) there is "fag", from which 

 recuperation is difficult, but possible; and (3) there is a fatal fatigue 

 when the over-worked cell collapses. The story of the bee's brain, 

 confirmed by Smallwood and by Mrs. Goodrich^ is a warning not 

 so much against over-industry, as against over-specialised industry 

 and too long hours. It is a warning against being over-busy — a 

 warning much needed by most men in North Temperate countries 

 who have very little of the resting instinct. This may be remedied 

 by a cultivation of the resting habit, in which connection it must 

 be emphasised that for young people the greater part of rest — 

 outside of sleep — should be a change of activity. 



Take another illustration of what one might venture to call 

 prophetic researches. There is an old problem like the origin of evil, 

 the problem of monsters. What is the cause of such ugly things as 

 creatures with one eye instead of two, or no eye at all, or one ear, 

 and so forth? There are several answers, such as the idea that 

 deficient nutrition at critical stages may cause "arrests of develop- 

 ment", as in hare-lip. But another kind of theory is suggested by 

 Dr. E. L. Werber's experiments on the American minnow. He sub- 

 jected the developing eggs to various re-agents, notably butyric acid, 

 and he got all sorts of strange monstrosities in eyes and ears, 

 nostrils and mouth, head and fins. The chemical intrusion seems to 

 dislocate and partially dissolve the essential germinal material, 

 especially at the head-end. Hence monstrosities. But the question 

 arises how any respectable embryo in natural conditions could pos- 

 sibly be influenced by anything at all like butyric acid. The answer 

 is that if something goes wrong with the carbohydrate metabolism 

 in the body, there may be a production of substances not very 

 remote from butyric acid ; and if the mammalian mother's constitu- 

 tion were thus poisoned, this might well cause monstrosities in that 

 mother's child. Thus, we have a zoological contribution towards 

 the mystery of monsters. 



Then there is the biggest fact of all that there is in wild nature 

 practically no constitutional disease among animals, and practically 

 no senility — a fact which medicine has not fully faced. 



But let us end on a lighter note. Long ago there arose in China 

 or Japan a mutation called the dancing mouse, and a hint of it 

 occurs occasionally among wild mice. The animal breeds true, and 

 is a fascinating bundle of peculiarities. It is quite deaf, except for 

 a day or two in early life ; it is given to excessive waltzing. Repeatedly 

 it has been reported that the dancing mouse has only one semi- 

 circular canal well developed, that it has something wrong with its 

 cochlea, that it has a peculiarity in the auditory centre of the 

 brain, and so on, but further investigation seems to have shown that 

 its ear and brain and other parts are structurally quite normal. It 



