162 Scientific Proceedings, Royal Dublin Society. 



serving to build up new plants and animals. Were it not for this 

 destructive work, accomplislied by the Schizomycetes, all the avail- 

 able carbon and nitrogen would long since have been absorbed into 

 organic compleses, and life have probably ceased to exist on the 

 planet. Again, it is not merely the life processes of those fungi 

 which influence humanity ; the by-products of these life-processes 

 are in many cases organic compounds of relatively high stability, 

 and capable of exercising the most intensely poisonous effect on 

 the economy of the higher animals. We gaze with interest on the 

 plant Strychnos Nux-vomica, growing at the Botanic Gardens, 

 because we know its cells have the power of calling into existence 

 a virulent poison. Why should we not have it in our power to 

 examine with equal closeness the Bacillus tetani, a vegetable which 

 grows in every field and every garden, and which elaborates a 

 substance of which it is safe to say that it is much more poisonous 

 than strychnine, and causes annually far more deaths ? We can 

 study at will Atropa Belladonna, the Deadly Nightshade : but the 

 plant which produces the far more virulent diphtheria-poison is 

 not cultivated in this country, save indeed in the bodies of those 

 whom it attacks. Apart altogether from the economic interest 

 attaching to the Schizomycetes for the reasons just alleged, there is 

 a purely biological feature possessed by some of the species, of so 

 extraordinary a character, as to justify their exhibition, as part of 

 any fairly complete collection of natural-history objects. As is 

 well known, since the researches of Pasteur, many Schizomycetes 

 can, and do, live and thrive in the complete absence of free 

 oxygen : while some there are to which the presence of that gas is 

 insupportable. It is not that their life processes are different from 

 that of all other living organisms, for they do consume oxygen, but 

 obtain it by decomposing the organic molecules with which they 

 are in contact, instead of, like all otlier plants and animals, taking 

 it from the atmosphere. 



Sufficient reasons have, I think, been now adduced why 

 thread- fungi, yeast-fungi, and fission-fungi should be included in 

 museums. The hitherto insurmountable objection to their exhibi- 

 tion has been their exceeding smallness, and the main purpose of 

 this paper is to show how this drawback can be obviated and the 

 species made accessible to the naked eye of the untrained observer. 

 The method I propose is to show, not the individual organisms 



