466 On Rust in Corn, ^-c. 
If we reason from analogy, this hypothesis carries with it the high- 
est degree of probability, for as water contains myriads of organized 
living creatures, invisible to the naked eye, so in like manner may 
the air also be filled by them. And why not these aerial animalcules 
deposit their eggs in a fluid, stored with proper nourishment for their 
offspring during the first stage of their existence, — when the gnat lays 
its eggs in the water, where they are hatched, and its infant brood, 
after a series of transformations as an inhabitant of the water, assumes 
its winged form, and becomes an inhabitant of the air ? 
I will not, Gentlemen, trespass longer upon your attention, but 
conclude by subscribing myself 
Yours, respectfully, 
John Smithurst. 
Lea, Jan. 18, 1832. 
Article II. — On Rust in Corn, 8;c. By James Rennie, 
Esq. A.M., A.L.S., Professor of Natural-History, King's 
College, London. 
Gentlemen, 
Last season, wheat crops were extensively infested with a 
parasitical fungus, popularly termed the Red Rust, — and as usual in 
such cases, the most improbable and impossible causes were assigned 
for this, such as blighting winds, which could no more generate this 
fungus, than they could have generated a crop of the wheat which was 
infected with it. A notion like this is injurious, in so far as it para- 
lyses the efforts of the farmer to obviate the evil, "it being impossible 
to prevent a blighting wind fi-om blowing through his crops," and ha- 
ving made up his mind that this is the cause, and the only cause, he 
thinks it would be lost time, and folly, to search after any other. It 
would be hopeless to reason with those who obstinately persist in hold- 
ing such an opinion ; yet this does not appear to me to be so bad as 
another opinion to which I shall briefly call your attention, as injurious, 
by leading to extensive practical error. 
This opinion, or rather theoretical fancy, being, that the Red Rust 
which infests grain, is identical in species with numerous other fungi 
found on the leaves of other herbaceous plants, and even on the leaves 
of trees ; and this fancy has been extensively propagated in books on 
agriculture and on botany, by those who either sei-vilely copy from 
others, or what is much the same, make their observations with their 
