26 MASSACHUSETTS AGRICULTURE. 



pestilence or famine. They are more fearful than the devour- 

 ing fire. They belong to a class of plants called fungi, 

 parasitic destroyers all, the scavengers of the vegetable 

 world. It is such a mould as you may see in autumn, at 

 once the murderer and shroud of the flies dead upon the 

 window-pane. Other fungi, not indeed of the special forms 

 of mould, are the "rust" or smut of cereal crops. The 

 remaining difficulty, after the discovery of the potato-mould, 

 the Peronospora, was to understand the full process of its 

 reproduction. Winter, in theory fatal to the life of any 

 ordinary form or germ of the potato-fungus, only laid the 

 chill of a brief interruption on its devastating work. There 

 must be, so botanists say, some secret retreat of vitality, some 

 conserving organ or seed, out of which the spring called the 

 evil powers into activity again. The riddle has just been read 

 by Mr. Smith, an English botanist of some repute. 



In the stems and corrupting fragments of blighted potato- 

 plants, and under the dissolving influence of the autumn 

 rains, very small brown grains or spheres have been found, 

 developed on the mould-threads, just as these are ready to die 

 by frost. This is the preparation of the parasite for winter. 

 Everything else perishes. The mould and its dead host, the 

 potato, crumble away. The little spheres, only the thou- 

 sandth of an inch in diameter, survive, waiting patiently in 

 the frozen ground. In the spring they thaw and sprout, 

 taking possession of other plants in the same soil. The 

 microscopist I have named is the first to detect and expose 

 this wonderful resource of the short-lived but destructive 

 mould. It now becomes possible intelligently to press to 

 extermination this pest, as others, like the vine-mould and 

 the wheat-rust, have had their ravages curbed before. 



This instance may stand for many, all teaching the same 

 lesson. Even the most refined investigations of science may 

 have their practical value. The steel-maker has found a help 

 in the " bright lines " of the spectroscope, and a jury, search- 

 ing for blood-stains^ have learned to interpret its "absorption 

 bands." So the farmer of the future will, in common with 

 all earth's workers, subsidize science for protection and 

 defence. 



Your patient attention to what I have said deserves its 



