178 DEPARTMEXT OF AGRICULTURE. 



To use it, put in strong* alcoliol for ten minutes, then in distilled water 

 for the same length of time; free the central o])ening from water; place 

 in it a drop of the flnid ^o be cultivated, and cover it with a very thin 

 glass cover. Care must be taken to keep it perfectly flat. Place the 

 slide in a culture apparatus, in which water alone is used as the isolat- 

 ing fluid; let one end of a piece of sewing thread rest on the end of the 

 slide, and the other dip into the water. 



If the slide is to be used without being placed in a moist chamber, 

 the paper should be covered with a piece of thin sheet-rubber or oiled 

 silk, of the same shape and size, and with a corresponding opening. If 

 it be desired to use high powers, or to trace the germinations of a spore 

 found in examining a slide, the glass cover may rest on the slide, and 

 the blotting paper be placed on instead of under it. 



If it is desired to develop the fruit, the drop of alimentary fluid should 

 be small, and a groove should be cut in the paper to the edge of the slide 

 "to allow the admission of air. The amount of moisture can be regulated 

 at will by varying the size and number of the threads used to keep the 

 paper wet. This slide is simple, cheap, and susceptible of being so modi- 

 fied that it is available for almost every purpose for which a growing 

 slide is required. 



De Bary's growing slides were also used several times, and were very 

 satisfactory. 



Another form of development apparatus which was used towards the 

 close of our experiments consisted of a six-ounce glass beaker, having a 

 little water at the bottom, and hermetically closed by a piece of thin 

 sheet-rubber tightly stretched over the top. From the center of this 

 cover there was suspended by a thread a strip of thin blotting paper, 

 which had been pre%iously soaked in alcohol and distilled water, and on 

 which the material to be cultivated had been placed. The thread was 

 attached to the cover and the paper by Canada balsam. This is a sort 

 of isolation apparatus, and is more satisfactory than the one used by Pro- 

 fessor Ilallier. 



The material or substratum upon which the cultures are made, and 

 which is intended to furnish nutriment to the fungi, is of various kinds. 

 We used extract of beef, healthy blood, condensed milk, solutions of 

 cane and grape sugar, pulp of lemon, orange, potato, «&c., &c. 



The solutions of sugar used were made with crystallized sugar, and a 

 little tartrate of ammonia and ashes of yeast were added to furnish the 

 nitrogen and salts required for the growth of fungi. 



All the api)aratus W'as thoroughly cleansed previous to use, by wash- 

 ing with alcohol and freshly boiled distilled water, and the solutions of 

 sugar, milk, Ix'cf juice, «S:c., were thoroughly boiled; and, if filtered, re- 

 boiled before they were used. 



