NOTES. Ill 



a good shape. When all the required layers have been put on, 

 the cast is dried. Slow drying in free air and warmth is preferable, 

 and takes from twenty-four to forty-eight hours ; but quicker dry- 

 ing in an oven may be used if need be. When the cast is dry, 

 the inside is painted over with a coat of spirit varnish. The paper 

 is then cut from the mould at the margins, and the cast will be 

 found to have shrunk slightly from the surface, and thus be loose. 

 With care, it can then be worked out from the crevices and' 

 corners. The rough edges are next trimmed with scissors and 

 bound with blue paper. A thin layer of size is then painted over 

 the cast. As soon as this is dry, the necessary painting can be 

 carried out. Oil colours should be used, mixed with turpentine if 

 a dry surface is wanted, or mixed with plenty of megilp, and 

 afterwards varnished, if a moist surface is to be imitated. The 

 time required for making each cast is about the same with papier- 

 mache as with other materials." 



How ARE Young Spiders Fed ? — In my rambles for botani- 

 cal specimens in the last three years, many new and curious things 

 have been thrust upon my attention in the insect world, and these 

 I have recorded for future use. One fact in particular struck my 

 attention, and I herewith submit it to the readers of Science, partly 

 to record the fact, and partly to ask if any other readers have 

 ever observed a similar fact. We have been taught by the best 

 works on spiders, that the young of spiders derive their food 

 mostly from the atmosphere. The "Encyclopaedia Britannica " 

 confirms this view. 



On the 19th June, 1891, I discovered in a ploughed field an 

 enormous spider, of the Lycosidse species, which was ij inches 

 long. She presented a very curious appearance, being covered 

 with scores of tiny spiders from one end of her body to the other. 

 When I touched her with a weed stem, the young spiders scamper- 

 ed oft' at a lively rate, only to return when left to themselves. The 

 spinneretts and abdomen of the mother spider were greatly dis- 

 tended. Suddenly there was a copious flow of white liquid, which 

 the young greedily devoured. Examining the fluid under my 

 microscope, I was fully convinced that this was veritable milk, and 

 that this spider at least nursed her young, instead of bringing them 

 up on atmospheric moisture. I shall be glad to know if any 

 reader of Science has ever observed a similar occurrence. 



Naples, N.Y. John W. Sanborn. 



Purification of Water by Green Plants'". — The preva- 

 lent idea that green plants (flowering plants and algae) growing in 



*Pharm. /ourn., Nov. 5, 1894, p. 356. 



