THE GARDENERS’ 
CHRONICLE. i 
[Ave. 22, 
e Eod 
"for air, and the temp will be as 
low asis practicable. It will be much better than 
removing the crop to stables, or other buildings, and 
theré will be no danger from frost, which indeed 
would do no harm if it reached Potatoes in such a 
situation. 
The recommendations made last year as to this 
oint were not dissimilar; except that greater 
importance was attached to dryness than it de- 
served. No doubt Potatoes then clamped with 
lime and sand, or with turf ashes, or charcoal dust, 
were saved where others perished; but in truth 
earth of any kind will soon become dry, and remain 
dry with such precautions as we have recom- 
mended. In a low temperature, and with the ex- 
clusion of air, the chemical changes, be they what 
they may, which result in the rot of the Potato, 
cannot possibly go on to such an extent as to be 
practically important. 
WE publish elsewhere a report of the meeting 
held on Monday last to consider what means can be 
devised to assist the sufferers in gardens from the 
late hailstorm. His Royal Highness the Duke of 
Campnings took the chair, and was supported by 
the Right Hon. the Lorn Mayor. It will be seen 
that a subscription has been opened, which promises 
to be considerable. 
PROPER REPOSE F 
ARTIFICIAL TREATMENT. 
Ir is well known to most people that plants under 
artificial treatment cannot exist in good health long 
without a period of repose, and therefore various direc- 
tions have been given respecting the proper treatment 
of them, both as regards their maturation and rest ; or, 
in other words, the propor Stave zn Which a plant should 
be previous to its resting season, and how that rest 
should be produced, 
One person recommends withholding moisture ; 
another advises as much exposure as possible to solar 
influence ; a third, close confinement and high tem- 
perature; a fourth, full exposure to the open air, with 
all its vicissitudes ; a fifth says, confine the roots and re- 
tard over-luxuriance ; a sixth, divest the plant of a 
portion of its roots annually; a seventh says, pro- 
long the growing season by encouraging early growth ; 
and finally, an eighth says, thin out the top freely. 
Now, all of these directions may be very proper when 
rightly applied, and some. under peculiar circum- 
stances, but what is the young beginner to make of 
such conflicting directions, any one of which, if applied 
in excess, is well known to be injurious, more particu- 
larly as the various organs and wants of plants are so 
accurately adjusted by nature to each other, as to pro- 
duce one harmonising whole. For instance, if the 
plant be placed in an unfavourable situation as regards 
some of the elements requisite for its health (light, air, 
or shade), or if it receive an excess or a want of others 
heat, water, or cold), then, in proportion, will disease 
or ill-health ensue ; while, on the contrary, there are 
many gradations compatible with health, and yet some 
disproportions observable upon the whole ; for the pre- 
dominance of any one particular case, such as vigorous 
wth or a stunted habit, or over-fruitfulness—these 
all tend to modify the whole habit of the plant ; and it 
may be laid down as a general rule that that plant 
which is between the extremes of leanness and obesity 
is in the most proper state for resting ; for the least 
tendency to the one state or the other must be at the 
future expense of either growth, bloom, or fruitfulness. 
But how is a proper state of repose to be attained ? 
Heat, cold, moisture, drought, light, shade, and air, are 
necessary agents (so far as climate and atmosphere are 
concerned) for promoting health and vigour, and are 
all requisite, in various proportions (according to the 
nature of the plant), some under particular circum- 
stances for adjusting the habit of the plant; for in 
tropical climates the rainy season occurs when the sun 
is nearest, and consequently spring and summer are 
combined in one, while on the other hand the dry season 
answers the same end as a low temperature does in 
colder climates, by withholding moisture, and conse- 
quently suspending vegetation; therefore, if the 
plant belongs to the stove, withholding moisture, 
gradually, both from the soil and atmosphere for 
a short time, and admitting plenty of solar light 
and heat, are the most natural modes of rest- 
ing such plants. Again, while natives of the extreme 
tropics are subjected to such extreme changes, they are 
also in general much better suited for withstanding long 
drought, soon recovering and becoming vigorous on the 
return of moisture ; while natives of a milder climate, 
and which may be termed greenhouse plants, would 
perish from a much less drought ; therefore it is ob- 
vious that the same treatment is inapplieable, and that 
great caution should be used when the operation is per- 
formed upon natives of the colder regions. It is a much 
better plan to place such plants in a cooler situation, 
and to suspend the supply of moisture but slightly from 
their roots; but then they may be allowed to remain 
out of doors as long as there is no danger of their being 
injured by frost. 
All plants should be encouraged to make fresh growth 
directly they have done blooming, and when such is 
matured, they should be subjected to a period of rest, 
otherwise the blooming season becomes disturbed, which 
is indeed apparent by some of the shoots producing 
blossoms long before the general time of flowering has 
arrived, of course destroying the beauty of the plant.— 
ENTOMOLOGY. 
Tur Potato Turirs (called by Linnaeus, Thrips 
minutissima).—Everything connezied with the Potato 
has become of such vital imyortance, especially in dis- 
tricts where it is the etaff of life, that any facts bearing 
upon the subject are interesting to the public. Mr. 
Barnes’s observations relative to the Thrips conse- 
quently led me to examine the crops in various allot- 
ments in Oxfordshire, where I chanced to be at the time ; 
and the following are the results of my inquiries. On 
the 30th of July some diseased leaves of Potatoes were 
transmitted to me from Bicton, and I found several 
ochreous larve of a Thrips upon them, which I have 
now reason to believe is the Thrips minutissima. About 
noon I visited several allotments, where I had observed 
in many places that the leaves and stalks were spotted. 
On digging up some of the worst, we found only one 
diseased tuber, whieh was of a tolerable size, and two 
more the following day. The yield was small, and 
there was a very considerable number of small Potatoes 
not larger than Peas and Beans. 
Upon the leaves I found several larvze, and one per- 
fect Eupteryx solani, alsoa good many oval white eggs, 
singly and in pairs, on the under side of the foliage; 
they hatched in a few days, and were, probably, the 
larvee of Sesva balteata. After a diligent search, I 
detected the larvee and pupa of the Thrips, together 
with the perfect insect, amounting, perhaps, to 20 spe- 
cimens. he Thrips was most abundant where the 
plants were sheltered from the wind, and invariably 
upon leaves in perfect health, The following morning 
I went, between 8 and 9, to look again for the Thrips, 
but found very few ; there were, however, many of a 
minute Smynthurus, some of them ochreous, with black 
eyes; others were as black as soot, with ochreous 
horns, and they were not larger than a grain of sand. 
In another spot, where the leaves had died, and the 
haulm was spotted, I did not find one bad Potato 
amongst those we dug up, nor a single Thrips on the 
green leaves of a few healthy-looking plants, and it was 
remarkable that the self-sown Potatoes in the Wheat- 
stubble did not appear to be in the least affected ; there 
were no symptoms of the Botrytis upon them. When 
I returned home on the 6th of Aug., my Potatoes 
looked healthy, which they did up to the 9th, with a 
few spots upon the leaves : but on the 10th they were 
completely blighted ; and the haulm was rotten in 
places oa the 14th. Previous to this I looked over the 
foliage, and found ‘larvee of the Eupteryx, but could 
detect only a solitary Thrips, and that was in the larva 
state. 
This larva is ochreous and shuttle-shaped ; the head 
is small and oval, with a minute black eye on each side,and 
a short beak beneath ; the horns are twice as long as the 
head, slightly pubescent and 4-jointed ; two first joints 
small ; third, egg-shaped ; fourth, nearly as long as the 
others united, ovate at the base, and attenuated to the 
apex ; thorax very long and broad, composed of three seg- 
ments, the first trigonate, the angles rounded ; the two 
following segments forming broad bands ; the abdomen 
is as broad as the thorax, composed of nine segments, 
conical and hairy at the apex ; six legs, short; thighs 
very short; tibice dilated ; tarsi indistinct or wanting ; 
fig. 2, magnified ; fig. 1, the natural size. 
The pupze are also ochreous, but when they change 
to the perfect state they are much darker, and such 
atoms that they are not easily detected under the 
leaves when at rest, and lying close to the midrib or 
nervures, but they run about actively enough when 
disturbed. ‘Thrips minutissima is entirely of a ferru- 
ginous or ochreous tint, excepting the abdomen, which 
is brown above, with ochreous spots ; the antennse are 
placed in front of the head, and are longer and slen- 
derer than those of the larvee, and six-jointed ; the 
joints are furnished with a few short hairs, the basal 
one is nearly concealed ; second, stout, obovate, obtuse ; 
three followiug, subelliptical and more slender ; sixth, 
the longest, attenuated to the apex, and appearing 
articulated ; head depressed, semi-orbicular, with three 
transparent ocelli; eyes large, black, lateral, and 
coarsely granulated; rostrum forming a short beak 
under the inclined face, close to the anterior coxæ, with 
palpi and mandibles, the bristle-like maxille passing 
through the rostrum; prothorax broader than the 
head, transverse, the angles rounded ; abdomen nine- 
jointed, broader than the thorax, elongate, ovate, the 
apex conical, bristly, and furnished with an ineurved 
ovipositor ; wings incumbent, and parallel in repose, 
J late, semi- 
pubescent legs, remote, clear ochreous ; posterior cox 
Zpproximating ; thighs broad; tibie clavate; tarsi 
rather short and slender, biartieulate; second joint 
bladder-formed. Fig. 3, the natural size; fig. 4, mag- 
nified, and represented flying. ij 
These insects, although notextensive in varieties, occa- 
sionally appear in vast numbers. On a former occasion 
I described and figured a species which does much mis- 
chief to wall fruit, and another that is very injurious in 
hothouses, and every cultivator of Melons and Cucum- 
bers is too well acquainted with the ravages committed 
by one of these little creatures, which blights the leaves, 
causes them to shrivel, and destroys the plant. The 
Thrips being provided with a short beak,which it thrusts 
through the cuticle into the stalk or leaf, extracts the 
sap in the same way as the aphides, and judging from, 
the depredations of other species, there can be little 
doubt that the Thrips may be quite capable of injuring 
the leaves and haulm ; but whether it causes the mischief 
which Mr. Barnes attributes to it, remains to be proved. 
We sincerely wish he may be able to establish his theory, 
asit would at once relieve us from the apprehension 
that the Potato is worn out, that it can be no longer de- 
pended upon as a healthy crop; and we should. then 
know where to look for a remedy. Possibly this Thrips 
revels at an earlier period in the Potato blossoms, as it 
inhabits the flowers of theWallflower, Chrysanthemum, 
Leucanthemum, &c. It has a natural enemy in the 
little shining brown. larva of a bug. I saw one which had 
pierced the larva of the Thrips, and ran about with it 
sticking upon its proboseis.— Ruricola. 
ON THE ORGANIC COMPOUNDS WHICH CON- 
STITUTE THE NUTRITIVE PORTIONS OF 
THE POTATO. 
By the Rev. Prof. HENsLow. 
(Continued from p. 549.) 
ALL animals have a function to perform which is quite 
as important to the preservation of their life, and, iue 
tethan the tion of 
even morei ly impor p 
the wasting tissues of their bodies—and that is * respira- 
tion.” Now, starch and other ternary compounds may 
supply us with the material which is especially neces- 
sary for maintaining respiration, quite as readily (an 
perhaps more so) as we may obtain it from any of 
those compounds which are considered to be modifica- 
tions of protein. "The material to which I now allude is 
carbon. Every time we inspire, a certain amount of the 
oxygen in the atmosphere is fixed in our blood ; and 
every time we expire, we discharge a like amount of 
carbonic acid, which has been. formed by the union of 
carbon (obtained primarily from our food), with the 
oxygen obtained originally from previous inspirations. 
This carbon may have been derived from the decompo- 
sition of various organie matters, whether composed of 
three or of four elements. hen obtained from the 
former class, there are two elements, oxygen and 
hydrogen, that become superfluous ; and when obtained 
from the latter, the same two, together with7{the 
nitrogen, are also superfluous, so far as the function of 
ipiration is T d. These superfi elements 
are discharged from the system, either in their free 
state, or in various combinations. The amount of ear- 
bon required for the function of respiration is extremely 
variable according to the conditions under which the 
human frame may be placed. In cold regions it is very 
much greater than what is needed in warm climates + 
and under active exertion a much larger amount is 
necessary than when we are comparatively inactive. 
In ordinary cases, it is stated that an active man in & 
temperate climate requires daily nearly 15 oz. of carbon 
(that is to say nearly a pound of this element) to supply - 
him with breath and warmth sufficient for robust 
health ; whilst a delicate female, remaining inactive; 
would not be in need of more than about a third of that 
quantity, say 5oz. I place before you two bottles, filled 
respectively with 50z. and 15 oz. of lamp black, which. i$ 
the substance nearest to pure carbon I can readily com- 
mand; and you may judge how large a proportion of our 
daily food must be appropriated for the support of 
respiration alone, You will recollect that this amount 
of carbon is in combination either with two or wit 
three other elements when it is introduced into the 
system under the form of food, and consequently, what 
you now see is only a certain portion of the actua^ 
quantity of matter that is really required for this pul 
pose. I do not find that the limits to the amount of 
protein required for the nourishment of our bodies have 
been so accurately determined as ‘those to the carbon 
necessary for our respiration appear to have been; 
but, as it is stated, that not more than 4 or 5 ounces 1$ 
needed by active men, I presume that a very scanty 
supply of this material may be all that is really neces- 
sary in many cases. In all speculations upon what i 
necessary for securing an adequate supply of the mate- 
rials essential both to respiration an ishment, We 
must not omit the important part that is played by the 
digestive organs, These are so variously modified a 
different animals, and even in different individuals © 
the human ‘race, that some organic substances whic! 
afford a wholesome diet to one person prove noxious 07 
even deadly poisonous to another. The speculations we 
are here reviewing presuppose the digestive organs ta 
i imilating th 
be capable of d posing an e partict* 
lar kinds of food that are brought under discussion, yen 
n 
that whatever carbon or protein they contaü 
iated 
to the purposes of respiration oF of 
longer than the body, very narrow 
, 
transparent, pale tawny; superior the broadest, pubes- 
cent, with two nervures, costa bristly; inferior margin 
and apex with long cilia ; underwings with one nervure, 
bristly, and ciliated like the others; six short, stout, 
e approp 
nutrition respectively. ions to 
I shall now endeavour to apply these speculations it 
the Potato, as an article of diet; and then compare 4 
with a few other substances of a vegetable and anima 
—— 
