98 THE AMERICAN MONTHLY [Apr 



next washed in absolute alcohol, and cut with a scalpel 

 that has been sterilized in a flame. A platinum needle is 

 dipped into the cut, and gelatine, previously prepared 

 with a decoction of leguminous shoots, is streaked with 

 it. The bacillus radicicola, being an aerobic form, requires 

 a large surface of gelatine for propagation. A pure cul- 

 ture is obtained in a few days. To inocculate plants with 

 the microbe, the bacilli are transferred to water, and a 

 little of the mixture is sprinkled over the soil in which 

 the plants are growing. 



Aphides. — Minute soft-bodied insects do not lend them- 

 selves to methods of preparation that will enable them 

 to be kept in a condition serviceable for subsequent scien- 

 tific study. Alcohol deprives them of their color, and 

 balsam frequently distorts, and so destroys the character- 

 istics of venation and of jointed appendages. The method 

 of roasting by the sudden application of intense heat 

 has hitherto proved itself to be one of the best means of 

 dry preservation. For Aphides the following procedure 

 gives satisfactory results. The living Aphis is put on a 

 sheet of white paper, and at the moment when it is in 

 the desired position the paper is held over a flame, and in 

 an instant it will be dead and will retain the attitude. 

 Then put it, still on the paper, into an oven ; or, still bet- 

 ter, hold it over the heated tin, carefully watching the 

 drying and moving the paper about in order to prevent 

 it getting singed. The roasting is quickly accomplished 

 in either way. If the paper burns brown it is a sign that 

 caution is requisite. To pierce those brittle preparations 

 is hazardous, and it is a better way to mount them with 

 gum in a dry cell. 



Heronite. — In the course of some petrological inves- 

 tigations on the north shore of Lake Superior, Mr. A. P. 

 Coleman discovered a new mineral, at Heron Bay, Lake 

 Superior,which he has named Heronite, and which he de- 



