1892.] MICKOSCOPICAL JOURNAL. 121 



aid of heat ; mix well and filter, while still hot, through paper 

 previously moistened with distilled water ; the whole should be 

 kept in a hot chamber whilst filtering. — Martiiuiale. 



Dead Black. — To 3 grains of lamp-black add 3 drops of 

 gold size and thoroughly mix. Then add 34 drops of spirits of 

 turpentine and mix. Apply witli a tliin camel-hair brush. 



Smith's Method of Drawing. — Place the body of the mi- 

 croscope horizontal ; remove the mirror ; put the slide on the 

 stage; condense the light upon it by means of the bull's-eye, tak- 

 ing care to centre the light ; attach the concave mirror to the front 

 of the eye-piece by means of a spring or a piece ^of thin wood. 

 Have its surface at an angle of 4^;° with the plane of the anterior 

 glass of the ocular. This will project an image of the object on 

 the paper beneath. If the outer ring of light is circular, there 

 will be no distortion. With a black cloth exclude all outer light, 

 covering both your head and the instrument. Mr. Hopewell 

 Smith draws any section easily in this manner, including magni- 

 fications of 600 diameters. 



BIOLOGICAL NOTES. 



Fungus Study. — In all the agricultural experiment stations i 

 the microscope is an important instrument. In no respect is 

 botany advancing to-day as in the study of the life-history of the 

 vegetable pests that send their unseen spores everywhere. Pi^of. 

 Halsted has given in the Botanical Gazette for April some of 

 the habits of fungi and has shown how the harboring of certain 

 weeds induces the multiplication of fungi parasitic to them, and 

 how the spores thus produced are carried to cultivated plants. 

 Thus 41 species of plants, many of them common weeds, harbor 

 that fungus which, when transferred to lettuce, is known as mil- 

 dew. The whole history of the fungus thus becomes interesting. 



Agassiz was once asked to write a text-book in zoology for the 

 use of schools and colleges. Of this he said: "I told the pub- 

 lishers that I was not the man to do that sort of thing, and I told 

 them, too, that less of that sort of thing which is done the better. 

 It is not school-books we want, it is students. The book of na- 

 ture is always open, and all that I can do or say shall be to lead 

 young people to study that book, and not to pin their faith to any 

 other." — F^'om '•'• Agassiz at Penikese" in Popular Science 

 Monthly. 



Salmon and Sturgeon in Idaho. — Prof. C. Hart Merriam 

 saw sturgeon at Lewis Ferry on Snake river, Oct. i^J, and learned 

 that individuals were at times taken weighing 600 pounds. He 

 saw several tied to stakes by their tails, one of which weighed 

 150 pounds. The fall run of salmon reaches that place about 

 October 10 ; thosQ that do not die go back in November. Indians 



