ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 535 



nature, is in all probability also an appropriate one for the cultivation 

 of the fungus, and one can in many cases make a nutrient solution by 

 cooking the substratum. For example, the dung of herbivora is a 

 very fertile nutrient soil for a variety of fungi, and a decoction of it 

 made clear and freed from fungi by sterilization, is a very good 

 nutrient medium. Nutrient solutions can also be made from sweet 

 fruits, e. g. plums, raisins, &c., of which a watery extract is made, and 

 sterilized by heat. The free acids of the fruit check the development 

 of many fungi. Beer- wort is also a convenient culture-fluid, but is 

 difficult to clarify, and when cooked forms a precipitate. Again, a 

 decoction of yeast, with more or less sugar, or a weak solution of 

 meat- extract, with or without sugar, may be used : or bread, which is 

 not acid, and which has been placed in an air-bath at 150^ C. for 24 

 hours. Lastly, one can use a variety of organic and inorganic com- 

 pounds. Many fungi flourish in acid solutions, while even a trace of 

 acid prevents the germination of the spores of others. 



Brefeld purifies the vessels, &c., used in cultivation experiments, 

 by boiling water, heating, or placing them for some time in 10 per 

 cent, hydrochloric acid, and afterwards scalding them in distilled 

 water. The methods of cultivation and study of spore-formation are 

 entered into, and the means by which impurities from access of air, &c., 

 can be prevented are minutely described. 



Net for Microscopists.* — Mr. H. A. Walters first tried a deep 

 conical net, stretched upon a framework of cane, bent (after boiling) 

 somewhat to the shape of an iron hook O-.. Across the open 

 portion, a copper wire, not less than six inches in length, was stretched, 

 which served as a finer cutwater than the cane, and made a strong and 

 effectual " scraper " for such stems as those of the water lily. Ho 

 found, however, considerable difficulty in turning a net of this shape 

 inside out, and, to overcome this, contrived the following one. 



The framework is the same as the first. The muslin bag is so 

 arranged that the point of the cone comes exactly opposite to the 

 centre of its mouth when stretched out behind it, and within this 

 point is inserted a 1/2 in. test-tube having the bottom ground off. The 

 ends of the muslin for 1/2 in. are bound tightly round the head of the 

 tube ; the projecting rim of the glass preventing it from being pulled 

 out. Round the whipping is placed a broad band of cork, a wine 

 cork, with the centre burnt out, and the edges bevelled forward to 

 prevent undue resistance to the water, which keeps the tube always 

 behind the muslin, and ready to receive the contents of the net; 

 otherwise, when the net is moving very slowly in the water, the 

 tendency of the tube is to sink below the mouth, thereby causing all 

 animal life to be merely washed in and out again. The tube is closed 

 by placing a square of muslin over the open end, and securing it with 

 a very small band of indiarubber. Duplicates of both muslin square 

 and elastic band are indispensable, these being the two most important 

 parts of all. Care should be taken when cutting the muslin that the 

 piece coming from the wire is quite flat and remains so after being 



* Sci.-Goasip, 1885, pp. 78-9. 



