EXPERIMENTS WITH CRYPTOGAMIC GROWTHS. 159 



security ; for we have repeatedly caused spores of various species of fungi to germinate 

 after they had been one or two minutes in alcohol; and spores being not easily wet by 

 water, they would readily pass without injury in a bubble of air drawn through any aque 

 ous solution. The risk of spores passing through an inch of dry cotton loosely packed in 

 a tube, unless by the aid of a strong and long-continued current of air, is probably very 

 small. 



Of course the most satisfactory proof of the presence of fungous germs in the blood 

 would be to see them actually develop under the microscope, and produce the forms by 

 which they could be identified. To this end we have made use of the various forms of 

 growing slides known to microscopists, but with results not very satisfactory. For the 

 general purposes of a growing slide, that which has given the most satisfaction is made 

 by laying on an ordinary glass slide, three inches by one, a piece of thin, fine, white 

 blotting paper of the same size, with an opening in the center three-fourths of an inch in 

 diameter, or a little less than that of the thin glass cover used. The edges of the paper 

 may be cemented to the glass with a little Canada balsam, although this is not necessary. 



To use it, put in strong alcohol for ten minutes, then in distilled water for the same 

 length of time; free the central opening from water; place in it a drop of the fluid to 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 

 isolating 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 germi 

 nations 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 modified 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 toward 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 previously 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 Professor Hallier. 



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, pota 

 to, &c. 



