68 



of these parasites attack man himself, as shown in the production of various kinds 

 of ringivorm and thrush. The belief is growing that diphtheria, cholera, low 

 fevers, and other such complaints, may be caused by microscopic funguses. It is an 

 unhappy fact, that these parasitical pests take up a residence on those vegetables 

 that are the most useful to man, viz., those which produce starch. Of these the 

 cereals are the most imjKjrtant. Rust and mildew attack the leaves, stem, and 

 bracts, while ergot, smut, and bunt attack the organs of fructification of barley, 

 wheat, rye, oats, maize, rice, and other cereals. The corn rust and mildew are the 

 same species of Puccinia in ditferent stages of growth. It may Ixj found on almost 

 every grass in every part of the world ; it seems to have a preference for wheat. 

 General attention apiMjars to have been directed to it for the first time in 1804, 

 when Bauer made drawings for (ieorge III. The wheat of that year contained 

 only 004 parts of starch and gluten in 1,000 parts, instead of tlie 9'J5 parts of the 

 nutritious matter which it ought to have contained. In IHOfJ the quantity was 

 abB<jlutely reduced to 203 parts. In 1810-11-12, when wheat was at its highest 

 price during the war, com rust was so prevalent and severe, the foliage of the 

 plants s(i eaten up with it, and in conse<iuence the grain so small and shrivelled, 

 that, much as it was wanted, it was not considered worth while to thrash it out. 

 It has txien notice<l that severe attacks of c<jm rust must have more than once 

 \mh;i\ c<jincideut with the aj)|)carance of cattle plague. The last time tliat the 

 cattle plague was prevalent in tliis country the clothes of jx'ople walking through 

 corn fields became orange coloured from the dusty spores falling on them. Smut 

 is individually a very minute fungus, ant! yet of all the corn parasites most readily 

 attracts attention. It is a si>ecies of Ustilago that attacks the antliers and ovaries 

 of wheat, l>arley, oats, maize, and rice, plants wliose fertility and well-doing are of 

 the utmost imi>ortance. It appears as a white viscid fluid, which dries up into a 

 swjty, pulverulent mass. A (jerman some years since attempted t<j prove tliat 

 this {Kjwder was simply a collection of diseased cells, and therefore not a fungus, 

 but he was easily refuted, for he was shown in tlie miscroscoixj the germinating 

 spores. 



Bunt (Tilletia caries) is a concealed foe, its residence is in the growing seed, 

 and it is not till the farmer takes his sample after threshing, that he detects the 

 presence of this pest (the little bunch of pappus at the upi)er end of the seed is not 

 white, as it ought to Ix', but dark and dusty). On careful search he then finds 

 some distorted grains containing a fuitid jxjwder, which, under a microscope, is 

 seen to consist of brown reticulate sfxires. Of course the presence of much of this 

 fungus would be detected in the flour by its ctjlour and smell, but the miller gets 

 rid of the affected grains by rolling and blowing. This fungus lias not been de- 

 structive for some years. 



In northern and cold countries where the soil is poor, rye is almost the only 

 cereal g^wn. This grain is i>eculiarly liable to the attack of a fungus called 

 Ergot. It is often present in such large (juantity that when ground u|) and eaten 

 a train of peculiar symptoms is produced called ebgotism, and instances are men- 

 tioned in which the continued use of the diseased grain has caused death. The 



