66 



but still further from M. Bauer's investiga- 

 tions. He says the one hundred and sixty- 

 thousandth part of a square inch contained 

 forty-nine of them. Hence he calculates that 

 not less than seven millions eight hundred and 

 forty thousand would he required to cover a 

 square inch English measure. It has, indeed, 

 been a question with some persons, whether 

 these appearances are not due to a mass of 

 diseased cells, and that they are not fungi at 

 all. But the answer to this is, that diseased 

 cells would not germinate, which these uredines 

 unquestionably do. There is no apparent dif- 

 ference, generally speaking, between the spores 

 of this uredo in wheat and barley ; but there 

 is certainly a degree of dissimilarity in those 

 delineated in the figures before us. This is 

 probably due not to the difference in the fungi 

 themselves, but to the matrix where they grow; 

 and there is great reason to believe that the 

 produce of fungoid matter does vary in this 

 manner, and even to a greater extent, with the 

 peculiarities of the matrices by which they are 

 nourished. If the spores of this uredo are so 

 small, what must the sporules be as to dimen- 

 sions ? The highest imaginable power of a 

 microscope could only be expected to exhibit 



