July 2, 1894.] THE TROPICAL AGRICULTURIST. 
15 
other plants cultivated and wild. The great difficulty 
consists in a systematic classification of those dimi- 
nutive organisms, whose generic and specific dif- 
ferences consist chiefly in the mode of forming the 
organs of reproduction, which unfortunately do not 
at any time submit themselves t> the view of the 
observer. 
All this helps to demonstrate that the said studies 
are connected with the most delicate operations of 
histological technicality, as well as with the most 
intricate problems of vegetable biology. 
I know as well as any one, Mr. Minister, that the 
discussion upon which I have entered would not 
afford much utility or interest unless accompanied 
by proofs, drawings, and typical samples, and for 
this purpose I would attract the attention of your 
honour to the collection, such as it is, of dri-'d 
leaves placed in the national herbarium, along with 
various vessels containing numerous samples of the 
diseased organs, preserved in spirits. 
I conclude this preliminary account, compiled in 
great haste, trusting that those interested in our 
national agriculture will keep a watchful eye upon 
the precious coffee trees which cover part of this 
beautiful country, so that, at the first signs of a 
disastrous epidemic, it may be combated with ex- 
pedition, and the principal source of the public 
wealth be preserved. 
I am, Mr. Minister, with all respect and consideration, 
Your obedient and' faithful servant, 
A. Tonduz. 
San Jose, 27th September 1893. 
Appendix. 
The preceding account was already being printed 
when 1 came to hear of an article entitled " Disease 
of the Coffee tree," written by Professor N. Saenz, 
and reproduced in the Bulletin of the Minister of 
Finance, Public Credit and Support, of the Republic of 
Salvador (No. 1, March 1893). 
The work of Mr. Saenz does not appear to have 
attracted attention in Costa Rica, and as it turns 
out from the descriptive details given there that 
he treats of the same disease that I have studied, 
I thought it useful to reproduce here some extracts. 
Unfortunately the investigati ns of Mr. Saenz con- 
cerning the classification of the parasite are far 
from being conclusive. For instance, the author does 
not admit that the fungus belongs to the Stibum 
fiavidvtm of Cooke, because his personal observations 
induce him to believe that it rather resembles a 
I'erunuspora (p. 6. he. cit), Moreover, the same 
writer concludes his memoir by the reflection, truly 
strange from his mouth, that l: considering the 
observations that he had made of living specimens 
and the luminous labours of Mr. H. Marshall Ward, 
the idea had taken possession of him that our fungus 
might be the Hemileia vastatrix " (p. 12. loc. cit.) 
In order not to abandon the reserve I have put 
upon myself in this present account, with reference 
to the identity of the parasite, I will not take any 
part in this contradictory debate, until I know the 
opinion of the celebrated crypto zamist and micro- 
grapher, Doctor C. Cramer, of the Polytechnic School 
in Zurich (Switzerland), to whom I have just sent 
a collection of diseased portions of our coffee trees. 
However, I shall consider it a duty to devote to 
the investigations of Professor Saenz all the attention 
that they merit, and, should there te need for it, 
I shall not hesitate to recognise in my next account 
his right of priority in the discovery of the true 
parasite of the disease. 
Here are some paragraphs chosen from Mr. Saenz's 
article : — 
"The disease of the coffee tree known by the 
different names of spot, doip, frost, rust, Hook-rot 
and green-spot (?) has unfortunately sufficiently 
developed already upon various coffee estates in 
the interior of the Republic, occasioning true and 
undeniable ravages in the plantations, and the con- 
sequent injury to commerce and agriculture. 
Its origin is a parasitical fungus whose classifica- 
tion has been discussed a little, while as yet there 
js, hardly enough known about it, 
Observations made upon leaves coming from 
Oosta Rica and Venezuela, reveal that the fungus, 
which causes the disease in coffee, belongs to the 
genus stibum, investigated iu a memoir, presented 
by Mr. M. O. Cooke to the Linnean Society of 
London, upon the coffee diseases of South America, 
in which are found the following lines : — 
" This stibum, whi''h has been called Stibum 
Jlavidum (Grevillea IX. p. 11, 18S0), has, like all 
the other species, a compound stem, formed by a 
bundle of slender filaments, parallel to each other, 
reunited in a shoot terminated by a globular head, 
made up of the free end3 of the component threads! 
subdivided and terminated by small subglobular 
spores. This corresponds very closely with the 
description of the parasite given by Professor Saenz, 
who notices the circular or elyptical spots of an 
ochre yellow colour and the hard points rising in 
the centre, which are the peritMciq of the sphaerella 
and the small fungi of a yellow colour, formed on 
a slender pedicle, crowned by a bundle of small 
fibres in which there are numerous oval corpuscles. 
The only difference lies in the size of these cor- 
puscles, which is double mine, a discrepancy not 
very important seeing that the measurement of such 
small bodies taken together is under consideration." 
The special cause of the development of the fun- 
gus is not known ; the active agent of it is a long- 
rainy season accompanied by a relatively low 
temperature. It has been noticed that the mischief 
almost always begins on the high or cold portions 
of the estate, or on p'antations with more than 19° 
C, after some crops and very soon the disease 
spreads rapidly to the neighbouring estates or plots 
favoured by a hard winter. 
The infection shows itself in a sometimes very 
considerable number of spots, round or tliptical, 
more or less irregular, of an ochry yellow colour,' 
scattered in great quantities over the branches', 
fruit, and the whole or tne greater part of the 
leaves, a-nounting to as many as sixty in a single 
leaf. Perhaps owing to the appearance of the 
diseased plant, to the shape and colour of the epot, 
the name of drop came to be given, for it looks as 
if a shower of some caustic liquid had fallen. 
At the beginning of the outbreak, and if tne plant 
is in good soil, there is nothing to fear for the 
time' being ; one and another leaf falls, and the crop 
suffers very slightly or not at all; perhaps from 
the mildness of the attack the planter is not suffi- 
ciently impressed with the idea of considering how 
the germs of the terrible evil may be destroyed 
neglecting it till it costs him very dearly. If the 
soil is not good, the outlook is much more serious, 
and sometimes fatal from the very commencement! 
In the first case the spot disappears at the end 
of winter and the approach of the dry and hot 
season, but reappears with greater vigDur at 
the return of the next rains ; and immediately a'so 
the hea'thy plants unde-go a marked transformation, 
a species of poisoning, for a 1 its functions suffer, 
the greater part of its leaves and fruit fall off, thus 
causing the loss of the larger portion of the crop, 
since the appearance of the fungus coincides with the 
time when the fruit begins to mature. Onthereturn 
of summer the bush revives, throws out new leaves 
and attempts to blossom, but very feebly. But if 
the plant is weak, it will not stand one, or at the 
most, two attacks of the disease ; generally it dies, 
unless after the first attack it is cut down to the 
collar or a little above, and then there is hope that 
the tree will return to its pristine vigour after 
three years at least, which is equivalent to starting 
a new plantation. It is not necessary to point out 
that the loss which the pianter incurs is almost 
ruinous. 
It may be said that the spot is a very capricious 
disease, since it attacks one or several" portions of 
the coffee estate, and indiscriminately all the bushes 
on a plot or only the half of a bush ; it is present 
in the nurseries, in patches of coffee new and old. 
planted on slopes, on the flat, or in hollows, in soii 
manured and unmanured, iu coffee in the open or 
under the shade of plantations, muches, guanos, 
