Page:Popular Science Monthly Volume 89.djvu/383

 Popular Science Monthly

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���attack of different species of parasites at dilTereut stages in their development, it has been necessary, in order to secure all of these, to import the host insects in as many different stages as possible and practicable. Importations of large cater- pillars, ready or nearly ready to pupate (go into a sleeping state) were first made in 1905. It was demonstrated during that year that they could be broug America with a degree of succc and that at least a proportion of the parasites with which they were infested could be reared.

One of the greatest diffi- culties, experi- enced from the outset, has been the ac- cl imatization of the parasites. The ones thus far cultivated have a tendency toward rapid dispersion over a wide area, thus hindering coloni- zation. Even though a large number of individuals are released, their spread is so rapid that the possibility of meeting and mating is soon lost.

Perhaps the most serious handicap to the progress of the work is the preserva- tion of the health of the assistants in the laboratory. The irritating and poisonous hairs of the brown-tail larvae, of which the nests are full, penetrate the skin of the assistants, entering their eyes and throats and almost filling the atmosphere of the laboratory. It was soon found necessary to keep the rooms thoroughly closed. Double windows were used, and the doors, too, were doubled, in order that a possible secondary parasite, if accidentally liberated, should have no chance of escape. This made the rooms very warm and increased the irritating effect of the larval hairs. Spectacles, gloves, masks, and even headpieces were invented, but they only increased the heat and were not entirely effective in keeping out the troublesome hairs.

��Spectacles, Gloves and Masks Are Worn by the Laboratory Workers as a Safeguard Against the Irritating Effect of the Gypsy Moth's Hairs

��Dr. Fiske finally devised an apparatus similar to an ordinary show case, the glass in one side being replaced by cloth with armholes, through which the gloved hands ol the worker could be thrust and the brown-tail nests handled in full sight through the top glass. Much of the rearing of brown-tail larvae must be carried on under conditions in which such cases cannot be used, the old difficulty exists.

is hoped that the introduced will in time prove sufficient for the purpose intended. Only events them- selves can be depended upon to answer this question. Un- fortunately the mothscontinue to disperse and multiply in the mean- time.
 * )arasites already

��Why Whiskers Continue to Be in Style for Cats

ALTHOUGH hirsute adornments of ,. all kinds, whiskers included, were once the real and indispensable thing, modern sanitary practice has made such inroads on unharvx\sted beards and long hair that only a few scattered humans such as musicians and soap-box orators still retain their hairy luxuriance. Not- withstanding this, however, the house cat has grown and nurtured its crop of whiskers or feelers for the last million years or so without bothering about hygiene.

The fact is that the cat's whiskers are absolutely necessary to it. The whiskers are as long as the cat's head is wide, and the head is as wide as the body, so wherever the whiskers go there may the cat go also.

The tiny, delicate hairs grow from a gland and are nerved to the utmost sensibility. No matter how light the touch of the hair against an obstacle it is instantly felt by the cat.

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