ON THE STUDY OF MICRO-FUNGI. 371 



compute 2,000 cups as occurring on each leaf, and suppose each 



cup to contain 250,000 spores, then we shall have not less than 



five hundred millions of spores on one leaf of the Goatsbeard.* 



Whether yEcidium lapsancB can boast of such a wealth as that, we 



shall not pause to consider, but the figures will give some idea as 



to the sort of numbers attained when the spores are actually 

 counted. 



If, now, we obtain some fresh specimens, and shake or brush 

 off the ripe spores at the tops of the cups into a little water on a 

 glass slip, we shall, without difficulty, be able to observe the ger- 

 mination of the spores. In order to confine a small quantity of 

 water for this purpose, it will be found very convenient to affix a 

 small indiarubber band to an ordinary glass slide with balsam or 

 some proper adhesive substance that will not readily wash off. I 

 have used cells made in this way for a considerable time and have 

 found them very satisfactory. When the spores are sown in the 

 water, the slide should be kept under a glass shade, in which a 

 dish of water is also placed to keep the chamber moist, so that 

 the water which is necessary to the germination of the spores does 

 not evaporate. 



In reference to these rubber-band wells perhaps I should men- 

 tion, by the way, that they answer very well for the examination 

 of pond water with low powers. They are easily made, and being 

 much stronger than many types of life slide, can be freely cleaned 

 without danger of breaking. The cover-glasses adhere closely to 

 the indiarubber, and do not slip off. When some active organism 

 is under examination everyone knows how difficult it is to keep 

 the creature under view in the usual sized well, as it gives such 

 ample scope for demonstration of agility. If, however, a portion 

 be cut out of an indiarubber circle, and a small hole be punched 

 in the segment, it will, when fastened on a sHde, provide a small 

 well, the whole area of which will be covered by the lens, and 

 consequently the creature will always be under view (see PI. XVII., 



Fig. 7)- 



But to return to the aecidiospores which we have placed in 

 water. They should be examined every now and then to see what 

 progress is being made. In two or three hours it will be seen that 



* Dr. M. C. Cooke, Microscopic Fungi, 1 870, p. 8. 



