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IV.— On Fibrous Covering. By C. K. Vacy, M.D. 
To the Secretary. 
[ This paper is inserted as containing very curious and original expe- 
riments in vegetable physiology, although the experience on which it 
is founded is not extended enough for the immediate adoption of the 
principle in practice."] 
Sir, — A short time since our president, Mr. Goldsworthy Gurney, at- 
tended the Council of the Royal Agricultural Society, and communicated 
some practical facts resulting; from experiments connected with " fibrous 
covering" on vegetation. The agency, whatever it may be, which pro- 
duces this remari^able action, is at present unknown ; and, until further 
iiiformation is obtained, we have called the supposed principle " Gur- 
neyism," to distinguish it from the practice ; the latter we call "Jibrous 
covering." The council expressed a wish to have more information on 
the subject : I believe all the information extant on this subject has ori- 
ginated, directly or indirectly, with our Society. The minutes of our 
proceedings have been taken, and tlie records are kept by me. Mr. 
Gurney has therefore requested me to communicate to you from these 
records in my possession and other available sources all the information 
I can give ; as he is at this moment unable to do it, being very pressingly 
engaged in other pursuits. 
I find that on the 7th of June. 1844, Mr. Gurney first called our 
attention to the singular influence of fibrous covering ; and in my 
minutes of our proceedings of that day, it appears that (after detailing 
some singular atmospheric phenomena connected with vegetation which 
he had observed in other experiments), he said, "if a bush or other 
fibrous matter were left lying in a field of grass, the vegetation beneath 
it would soon be observed to be finer and fresher than that around it. 
This was a fact known to every one, and had been noticed from time 
immemorial ; the agency by which this increase of growth was brought 
about, evidently involving some great and important but unknown prin- 
ciple, had never, in his opinion, been sufficiently investigated — indeed it 
had never been investigated at all. It was generally attributed to the 
shelter from the weather, or the protection from cattle, which the bush 
afi'oided. Men were satisfied on this supposed explanation, and no 
further notice, so far as he knew, had been taken of the fact. Neither 
of these causes had anything to do with the matter." He now detailed 
many experiments, showing this to he the case ; and in further explana- 
tion of the phenomenon, said, "if a rod of wood, iron, or any other 
material, be placed horizontally above growing grass, and supported 
about half an inch from the top, the rod would soon be observed to 
produce a sensible influence on the growth beneath. A rope, or indeed 
a line of any sort, would produce the same effect, no matter how sheltered 
the situation, or how protected from cattle ; two or three rods placed side 
by side would render the effect more sensible, and in a shorter space of 
time. The influence of a gate or harrow would be in the recollection of 
most of the members present, if left lying in a field of grass. The grass 
immediately beneath the framing would be seen to grow more rapidly 
