108 ANIMAL PARASITES. 



the chrysalis. The caterpillar also exuded this substance on 

 being touched with a knife on the black shields. On coming 

 into contact with the moist skin it caused, after eight hours, red 

 itching pustules, but produced no effect when brought in contact 

 with the dry or oiled skin. The dust loses its peculiar power by 

 being preserved in spirits of wine. Ratzeburg observed that 

 feeding the caterpillars shut up in a glass, and the necessary 

 repeated opening of the glass, were sufficient to cause inflam- 

 mation. Lameil, Physician to the Lunatic Asylum at Charenton, 

 observed, after the lapse of ten years even, on opening a glass 

 which contained a piece of a cocoon, similar effects. The micro- 

 scope shows the dust to consist of very fine, straight, spiry, 

 minute hairs beset with barbs. They are exceedingly light, swim 

 on water, and are sometimes carried away by the wind, flying 

 about for some time in the forest. The dust is carried on to 

 objects and into the air by the creeping of the caterpillar on a 

 damp place, by touching it, by moving through the air, and by the 

 falling of drops of rain on the bark. This dust seems, however, 

 only to be formed after the second and last casting of the skin 

 of the caterpillar. 



In places where the caterpillar is of frequent occurrence, the 

 animals which come into the forests are attacked by various 

 diseases. Sheep by inflammation of the eyes and violent coughing ; 

 cows and goats by the same symptoms, with internal inflammations 

 and ulcers all over the skin, the violent itching of which makes 

 the animals restless and drives them almost to madness ; horses 

 more especially suffer from it. The diseases of the eye caused 

 by it are blenorrhcea of the conjunctiva, dimness of vision, and 

 perforation of the eye. People become exposed to this poison by 

 staying in a forest, by sleeping, working, or taking a ride, 

 playing, cutting down wood even in winter-time, by gathering 

 fruits, as strawberries which grow under the oak-trees, by collecting 

 grass, litter, or the fallen leaves of forests. The diseases which 

 follow are violent inflammation of the eye, erythema of the eyelids, 

 blenorrhcea, coughing, inflammation of the throat and the lungs, 

 violent itching and scalding eruptions of the skin (nettle-rash) 

 and general fever ; children who wear no trousers incur inflam- 

 mations of the genitals, phymoses, leucorrhoea, and swelling of 

 the labise, and finally also angina membranacea. The question 

 is whether the above-described dust which is found, according to 

 Nicolai, more particularly on the edges of the black shields of 



