A PSYCHOLOGICAL STUDY OF FEAR. 77 i 



becoming corrupt, and in a properly conducted nursery the litter is 



kept dry. 



"Wrongly confounded with pebrine, the disease flacherie is still 



more destructive to silk-worms. The symptoms are remarkable. The 



rearing of silk-worms often goes on regularly up to the fourth molt, 



and success seems assured, when the silk-worms suddenly cease to feed, 



avoid the leaves, become torpid, and perish, while still retaining an 



appearance of vitality, so that it is necessary to touch them in order 



to ascertain that they are dead. In this state they are termed morts- 



flats. A few days, sometimes even a few hours, suffice to transform 



the most flourishing nursery into a charnel-house. Pasteur examined 



these morts-flats, and found that the leaves contained in the stomach 



and intestine were full of bacteria, resembling those O o & 



which are developed when the leaves are bruised ooco* <<, 



in a glass of water and left to putrefy (Fig. 6). * . ' \ J* 



In a healthy specimen, of good digestion, these 



, , x . . ,m m . , Fig. 6. Micrococcus bom- 



bacteria are never found. It is therefore evident bycis (Cohn), Flacherie 



that the disease is owing to bad digestion, and be- micro ia 



comes rapidly fatal in animals which consume an enormous amount of 

 food, and do nothing but eat from morning to night. The digestive 

 ferments of unhealthy silk-worms do not suffice to destroy the bacteria 

 of the leaves, nor to neutralize their injurious effects. These bacteria 

 are really the cause of the disease, for if even a minute quantity of the 

 leaves taken from the intestine of diseased silk-worms be given to 

 healthy specimens, they soon die of the same disease. It is, therefore, 

 essentially contagious, and, in order to prevent the diseased silk-worms 

 from contaminating the healthy by soiling the leaves on which the 

 latter are about to feed, as much space should be assigned to them as 

 possible. 



Good seed should also be selected, since it has been ascertained 

 that some lots of seed are more liable to the disease than others. The 

 affection does not indeed begin in the egg, as in pebrine, but the ques- 

 tion of heredity comes in. It is clear that, when a silk-worm has been 

 affected by flacherie without dying of it, its eggs will have little vital- 

 ity, and the grubs which issue from them will be predisposed by their 

 feeble constitution to contract the disease. 







A PSYCHOLOGICAL STUDY OF FEAE. 



By CHAELES EICHET. 



THE study of fear, although it is very interesting, has hardly yet 

 been made in a methodical way. While some ingenious observa- 

 tions concerning it may be found in moral and psychological works, 

 the physiologists and philosophers appear to have neglected this 



