Feb. r, 1895.] 
THE TROPICAL AGRICULTURIST. 
507 
pateut process, a process which, whilst combing out 
every impurity, retains the whole of the valuable 
fibre. This machine has been specially made for 
combing Rhea, and. being simple iii its mechani-'m, 
it will immediately recommend itself to people in- 
terested in the trade. A saving is thus effected of 
over 25 per cent, in waste, as -compared with any 
combing machinery now in use, an advantage the 
imp rtance of which, in its bearing 01 the future of 
Rhea, cannot be too highly rated. The product is 
at this point pe fectly ready for spinning oy any of 
the :ecognised mills. 
the different processes above described Messrs. 
Edwards RadcljrFe and .burrows undertake to treat 
the Rhea fibre as it is now imported. They h:ve 
not, however, stopped here, but are engaged in 
perfecting a machine which will enable the planter 
to treat the fibre on the ground as soon as it is 
gathered, and, under these favourable circumstances 
to there an 1 then produce the filasse, thus not only 
effecting an enormous saving in freight, but also 
sending into the market a material of better quality 
and higher value at a less cost than is now incurred 
in the initial separation and chemical dressing of the 
ribbons. 
Such authoritative judges as Sir He: ry Blake and 
Sir Augustus Adderley I ave expressed their cordial 
admiration and approval of th- processes which aro 
here described, as well as of an equally clever patent 
now being developed by the same inventors f r the 
treatment of the leaves of various tropical plants, 
such as the cactus, the pineapple, and the banana. 
By this machine, even in it3 present unfinished 
state, a cactus leaf of great size and thickness was 
in le;.s than a minute reduced to a mass of silky 
fibre, the ultimate successful preparation of which 
for tpinning will effect an absolut ; revolution in 
this vitally important bnuch of the commerce of the 
world.— European Mail, Dec. 26. 
THE DISEASES OF TREES. 
Those interested iu the growth of tree3, whether 
as park specimens or for timber-producing properties, 
will assuredly be interested in this valuable treatise,* 
Iu its German text it was known to a few, in its 
French dress to a few more, but it was high time 
it was made accessible to the English reader. In 
no other work that we are acquainted with, is the 
subject, within the limitations fixed by the author, 
treated so lucidly; in no other work are the details 
of the changos wrought by parasitic fungi in the fabric 
of the tree so carefully worked out. Previously to 
the publication of this work, there was little or 
nothing available for the use of the English student, 
but the papers on vegetable pathology compiled by 
the late Rev. M. J. Berkeley, and published in in- 
Bt '.lmcnts in these columns. As these papers ran 
through several volumes, and wero never separately 
reprinted, it is not now easy or convenient to study 
thcni, but for those who desire to do so, it maybe 
convenient to mention that a full analytical index 
is given at p. 677 of our volume for 1857. Since 
Berkeley took up the . subject, however, the life- 
history of many of the fungi concerned has been 
more thoroughly investigated, and improved methods 
of research and observation have been devised. 
Berkeloy's work, however, for the time at which it 
appeared was excellent, and more modern research 
has, in mauy instances only confirmed his opinion. 
In the present volume diseases are considered 
according to the causes that produce them, such as 
parasites of all kinds, wounds, faulty state of soil, 
or unfavourable atmospheric condition. Tin's is of 
courso a scientific mode of procedure, and in the 
long run the best in practice, for, unless the causus 
of the disease are known there can be no such thing 
as cure. Still, the forester and the gardener require 
in the first instance, to recognise the nature and 
* Text Book of the Diseases of Trees. By Professor 
R. Hartig (Translated by Dr. Someiville, revised 
and. edited by Professor Marshall Ward). Loudon: 
MuLiuillan &, Co. 1S'J4. 
symptoms, or rather the signs of the disease (for 
: symptoms are subjective, and as such, not forthcom- 
| ing in the case of plants), and these signs, though 
; by no means passed over in this volume, are yet 
hardly set forth with sufficient prominence for prac- 
I tical use. Take, for instance, the '•canker" of the 
| Apple or the Beech. There is iu this volume a 
| clear summary of what is known concerning the 
I diseased conditions, but it is placed either under the 
head of Nectria ditissima, or of injuries due to at- 
mospheric influences, but how few gardeners have 
ever heard of or seen the fungus ! Similarly, the 
appearances of Larch-canker are described under the 
head of Peziza Wilkommii — appropriately enough 
no doubt, for the initiated, but not so conveniently 
for those who perforce have to pass from the known 
to the unknown, and by whom the meaning of " my- 
celium," "hymenium," "gonidia," "spores," and 
even of "cortex" is only imperfectly if realised at 
all. The Editor of the present work has recognised 
this, for while not altering the plan of the volume, 
he has added in many cases explanatory notes ; and 
these, together with the brief summary of diseases, 
classified according to the plant, and part of the 
plant attacked, and an excellent index, do much to 
diminish the inconvenience we have alluded to. If 
in a subsequent edition the diseased conditions, as 
seen by the naked eye of an ordinarily good observer, 
could be described under a few general headings, 
such as "canker," "ulcer," "tumours," &c, before 
launching into details appreciable only by the trained 
student, the value of the book would be much en- 
hanced. 
The summary just mentioned is all too brief, and 
in subsequent editions this also should be largely ex- 
tended. For instance, a few years ago, apparently 
from some climatal cause, the Lombardy Poplars in 
this country, and, we believe, on the Continent, 
suffered great injury, and their upper branches died, 
as in the case of stag headed trees, We turn to 
the classified list of the volume before us, and under 
Populus pyramidalis (which, by the way, is hardly 
the correct designation of the Lombardy Poplar), 
the only statement ws find is, " The branch and 
twigs die. " A reference to a fungus Didyniosphaaria 
populina, described at p. 104, is given, but that 
description does not apply to the particular disease 
of the Poplar to which we refer. Removal of the 
heads of the trees in an avenue known to us checked 
the disease, and its traces are now no longer visible. 
So under Ulmus all the information about diseases 
of the Elm vouchsafed to us is this, " The leaves 
show vesicular blotches : Exoascus Ulmi." On turning 
to p. 135, as directed, we find, "Exoascus Ulmi 
produces outgrowths on the upper side of Elm leaves." 
One need not be a forester to know that this state* 
ment is meagre in the extreme, and that it does 
not exhaust the list of diseases to which Elms are 
subject. Under Crataegus, or Hawthorn, we find 
no mention of a very peculiar hypertrophy and 
hardening of the stem, apparently linconected with 
fungous attack. 
Whilst thus indicating a few of the weak places 
which frequent use of the original work has brought 
under our notice, we do so without the slightest 
intention to under value what is, so far as it goes, 
the best work on the subject in existence. 
The translation has been well done, and tho pre- 
face, by Professor Ward, is what a profaco should 
be, an introduction to what is to follow. Professor 
Ward, however, uses the term "pathology" in a 
sense which is not usual, but in this lie is not 
alone, viz., as the equivalent of abnormal physiology, 
or as the " study of disease," rather than as the 
result of abnormal or morbid physiological action^ 
The illustrations are excellent, and the work, as a 
whole, well got up. It will, wo hope, do something 
towards tho establishment hero ot a central insti- 
tute, with local branches, for the study of vegetablo 
pathology. In France and in Germany they abound, 
in tho United States they may be counted bv the 
score, but in this practical country wo have no such 
separate department, though the excellent services 
rendered incidentally by tho department at Kew 
cannot be over estimated.— Oai rfeiiffV C'hivnidc, 
