[buller] presidential ADDRESS 23 



so that on the piece of melon I had placed three kinds, on the quince 

 on five sides five kinds, and lastly on the pear on six sides six kinds, 

 just as is shown in the Plate of Mucor at the letters a, b, and c.^ 

 All these species of seeds began to germinate from the fourth to the 

 fifth or sixth day of the month, as I observed. They developed into 

 plants according to their seed, of which some attained to their maturity 

 on the tenth day, others on the twelfth, others on the thirteenth, and 

 finally others on the fifteenth : and they produced the seeds of their 

 kind. I kept these seeds separate, and again and again planted the 

 seeds produced in like fashion from them ; and then I always observed 

 the same mode of growth in them, not in one trial only but however 

 often and whenever I attempted it, without any difference whatsoever 

 other than in the rate of growth or in the earlier or later ripening. 

 These discrepancies could arise from various causes, perhaps from the 

 difference in the time of the year, the place, or the structure of the 

 substrata, or because the seeds were too ripe or immature. 



At the present time, in tracing out the life-history of a fungus, we 

 sow single spores in a sterilised nutrient medium and thus obtain pure 

 cultures. The progress of development is then watched step by step 

 with the microscope, so far as is necessary, until a new crop of spores is 

 produced. In particular it was by the successful employment of this 

 method that Brefeld and other modern investigators have taught us so 

 much. Micheli, on the contrary, made what we may call mass experi- 

 ments. He did not sterilize his nutrient medium, but by cutting a 

 piece out of a fresh melon or quince or pear he obtained a substratum 

 which was practically sterile. By sowing the spores of his Moulds in 

 thousands, he obtained a crop of new plants which simply swamped any 

 other weed-fungi which might have become planted by accident. 



The possibility of the fall of invisible spores upon a culture medium 

 from the air, which may germinate and produce plants, was fully realized 

 by Micheli as his remarks in his Observations IV, V, and VI show. 

 The way was thus prepared for the final overthrow of the theory of 

 spontaneous generation by Pasteur one hundred and fifty years later. 



The establishment of the true origin of fungi by means of the 

 highly original and ingenious experiments recorded in his Nova Plan- 

 tar um Genera will always entitle Micheli to a place in the front rank of 

 the founders of mycology. 



1 In my PI. IV, at J, K, and L. 



