36 
THE GARDENING WORLD. 
September 19, 1885. 
lie having been a prominent advocate of the temperance 
cause for a great many years. On the date named, 
there was a pleasant gathering at his residence, when 
sixty-five employees and friends were entertained to an 
excellent dinner, and during the course of the proceed¬ 
ings they showed their goodwill towards their venerable 
host by hearty congratulations, and the presentation 
of a handsome armchair. This was accompanied by an 
address complimentary to Mr. Barron as an employer, 
and expressing the hearty wishes of all the signatories 
for his continued good health and activity. The time 
of the guests was agreeably spent in the inspection of 
the grounds, conservatories, &c., and later in the 
evening tea was provided, and Mr. Barron took the 
opportunity in responding to the greetings which he 
had received of giving a most interesting sketch of his 
long life, taking care to inculcate the advantages to be 
derived from temperance. 
American Floristsand the FlowerTrade. —-At a recent 
gathering of American florists at Cincinnati, the presi¬ 
dent, Mr. John Thorpe (formerly of Stratford-on-Avon) 
is reported to have stated that 24,000,000 cut Boses 
were sold last year ; Carnation flowers, he thought, 
would reach 125,000,000 ; 200,000 dollars represent 
about the amount paid the Dutch last year for Hya¬ 
cinths and Tulips ; 700 people are supposed to be en¬ 
gaged in selling florists’ supplies, and there are probably 
2000 cut flower sellers. Florists have grown four-fold 
in ten years. Catalogues have increased five-fold ; 
these make trade for those who do not catalogue. 
‘ Florists are the most generous of human beings. Few 
people give so much of then ware to public institutions 
as florists. Still, it was a generosity that paid by the 
increase of floral taste. There were 2000 first-class 
gardeners in the United States, and thousands of 
amateurs without professional help. ” 
Hydrangea paniculata grandiflora, —This is probably 
the finest member of the genus, and certainly one of 
the best late summer-flowering deciduous shrubs with 
which our gardens may be beautified. When it is 
stated that a single truss or panicle of its white flowers 
often measures from 12 to 18 ins. in length, and that it 
is not unusual for old plants to produce from thirty to 
fifty such trusses, the value of the plant as a flowering 
shrub at once becomes apparent. We have seen fine 
specimens similar to those above noted literally borne 
down by the great weight of their broadly-shouldered 
panicles of pure white flowers. It is an excellent plant 
among shrubs generally, or planted here and there 
among Rhododendrons, and deserves a far more ex¬ 
tended cultivation than it at present obtains. 
The International Potato Exhibition. —This annual 
symposium of potatos will soon be here again, for the 
autumn is creeping onwards rapidly, and in about 
eighteen days the gathering will commence. This year, 
as last, the show will extend over three days, but as no 
practical inconvenience was then found, doubtless none 
will present itself this year. Those of our country 
friends who come up to town to exhibit, get a day 
longer, it is true, but they can, doubtless, find many 
methods of usefully employing the time. Arising from 
various causes, some material alterations have been 
made in the schedule, specially in the direction of 
limiting the number of classes into which any one 
exhibitor may enter, as it is thought, the not un¬ 
frequent sweep made by one or two competitors of all 
the best prizes, has a detrimental effect, and can hardly 
be regarded as otherwise than injurious to the best 
interests of the shows. A consolation class with good 
prizes attached, for any competitor who has never 
yet taken a first prize at any of the shows, will perhaps 
help to bring a few new ones into the field. On the 
other hand, the disappearance from the schedule of the 
most valuable prizes invariably offered by a leading 
firm will provoke surprise, but it is stated that the 
conditions under which such prizes were offered, this 
year were such as the committee, in justice to other 
trade houses, could not agree to. Certainly, in matters 
of this sort, it is a pity any kind of conditions should 
be affixed, as they materially detract from the merit 
which otherwise would attach to the prizes. Possibly 
the existing difficulty may be more amicably arranged 
next year, but. it is very evident that the show is 
altogether wanting in breadth of management, and 
should have a more fully representative basis ; if that 
be not provided it must soon die out. It is satisfactory 
to learn that, in spite of the dry season, growers are 
turning out very fine clean samples, and it is antici¬ 
pated that the show nil 1, in the matter of exhibits, 
display good average qualit}-. 
WET-ROT IN POTATOS. 
(Bacillus Amylobacter, Van Tieg.) 
Every intelligent gardener who reads something of 
the current literature of the day must be more or less 
acquainted with two subjects. The first is the wet-rot 
of Potatos. "When Potatos are lifted, it often happens 
that certain examples are quite soft, and filled with a 
white, filthy, putrid, sour-smelling, creamy liquid. 
Sometimes stored Potatos fall into the same loathsome 
and offensive condition. All gardeners by personal 
observation know only too well the sickening wet-rot 
at sight. The second subject is probably known only 
b}’' hearsay, or by reading ; it is the ‘ ‘ germ theory of 
disease.” It relates to highly microscopic organisms, 
chiefly termed Bacteria and Bacilli. A great number 
of very eminent men of science believe that many 
diseases of plants, as well as of men and other animals, 
are caused by the presence of the almost inconceivably 
minute fungi named Bacterium, Bacillus, &c. It is 
hardly likely that working gardeners have seen these 
minute objects in a living state; indeed, they are 
almost unknown to many regular workers with the 
microscope, for the reason that many of the parasites 
are so minute, that ordinary high powers of the micro¬ 
scope hardly show them at all. For their observation 
the very highest powers must be used, in conjunction 
with the very best arrangements for light, for if the 
best microscopic glasses are used, without the most 
critical lighting, very little can be done. The fungi 
to which we refer, however, easily take up stains ; 
a perfectly transparent fungus can be easily stained 
purple, red, or brown, and so be made more visible. 
One of the most eminent and justly respected 
botanists of the present time, Tan Tieghem, says that 
the wet-rot of Potatos is caused by^ a micro-organism 
named Bacillus Amylobacter. The name Bacillus is 
derived from the Latin word, Bacillum —a little staff. 
Amylobacter is derived from the Latin Amylum — 
starch, and Bactron —a staff or cane, hence Bacterium. 
The name really means, the minute rod or bar-like 
fungus which attacks starch. The Bacillus of wet-rot 
at certain times contains starch in its cells ; the 
existence of starch is proved by the iodine test. 
The accompanying illustrations show form and mode 
of increase of the Bacillus of wet-rot in Potatos. The 
drawing is enlarged to 1,000 diameters—a very high 
scale of magnification. It will be better understood 
when we say that two millions of the real objects could 
be placed side by side upon one side of the young 
Bacillus as seen magnified at A. 
The illustration above at A shows an infant rod, cell, 
cylinder or bladder of Bacillus Amylobacter ; it quickly 
grows in length to the sizes shown at B and C. When 
the length of D is reached, a joint appears across the 
middle as shown, ‘and the single rod then breaks up 
into a pair of rods as shown at E, and each of the newly 
formed pieces grows to the size shown at F ; when the 
size of G is reached, another joint is formed across the 
middle, and two new rods are again speedily set free. 
The Bacillus thus rapidly increases in number by divi¬ 
sion over and over again repeated. After the process 
of division has gone on for a considerable time, a large 
colony of Bacilli is formed (termed by botanists a 
zooglcea). This colony often excretes a slimy gelatinous 
hyaline material, and this material holds together the 
colony of living rods in one mass. The colony, or 
zooglcea state, is a resting, and not an actively vege¬ 
tating state. In this latter resting state, the rods 
change their form as at H, I, J. and K, these new 
forms each enclose a strongly refringent dark coloured 
roundish or oval spore or seed as shown. At length 
the spore frees itself from its investing membrane, and 
exists as at L, its old membrane or rod having perished. 
The spore now begins to swell and germinate, the basal 
part opens as shown at M, and the inner material pro¬ 
trudes ; further protrusion is shown at X. On reaching 
the length shown at O, a joint is formed across the 
middle, and then a new series of rods is commenced. 
These new rods now go on increasing in size, and 
forming new joints and individuals, till other series 
like A, B, C, D, E, &c., are produced, and so the pro¬ 
cess goes on indefinite!}'. 
When the wet, rotten, creamy, or pasty material 
taken from Potatos destroyed by wet-rot is carefully 
examined, this highly microscopic and curious fungus 
named Bacillus Amylobacter, is invariably found in 
prodigious quantities. 
A highly important question in regard to the fungus 
before us, is whether the Bacillus is capable of starting 
wet-rot in sound Potatos, or whether it is a mere 
accompaniment of putrifaction. The fungus is some¬ 
times seen in apparently healthy plants, but it is far 
more common in decayed plants and vegetable material 
in a state of putrescence. It is a well ascertained fact, 
that the Bacillus often works in company with the 
common potato fungi named Peronospora infestans, 
and Fusisporium Solani, two fungi which are remarka¬ 
ble, the first for setting up putrescence, and the other 
for greatly accelerating it. The Peronospora it is evi¬ 
dent often starts the putrescence which is favourable to 
the Bacillus. The Bacillus in turn is of such rapid 
growth, and is such a powerful ferment, that it not 
only destroys the Potato tuber, but it kills both the 
Peronospora and Tusisporium. 
The following facts, however, appear to be certain, 
when the Bacillus rods have a surrounding of water, 
they can attack the cell walls of the potato tuber and 
cause them to swell and dissolve. By this process the 
Bacillus sets free the starch granules of the potato, and 
these granules are in turn invaded and disintegrated, 
and so the soft putrid condition of the Wet Bot is 
brought about. 
As the creamy putrescent mass within diseased potato 
tubers destroyed by Wet Bot swarms with the living 
rods and spores of Bacillus Amylobacter, and as these 
rods and spores can break down cellular structure and 
destroy starch, it follows as a consequence that the 
disease is highly infectious, especially in damp positions. 
The evidence appears to entirely point in this direction, 
although it is possible that future and more searching 
observations may modify or somewhat alter our ideas 
as to the Bacillus being the sole cause of wet - rot. 
The common potato fungus, Peronospora infestans, it 
is well known can both break down vegetable cells and 
injure starch. 
Wet-Bot is common in the “ pies ” or pits of some 
districts, the fungus is kept alive and in good condition 
by the warmth and humidity of the pit, the moisture 
necessary for the fungus is supplied by the gradual 
percolation of the lain. When the spores of the 
Bacillus are once formed, they are capable either of 
immediate germination or of remaining in the ground 
in a living state for a long time. It is said that the 
spores can remain in a resting state in the ground for 
years, and then on the advent of favourable conditions 
germinate and resume active vitality. Dr. E. Klein 
says, the hybernation of the spores can be prolonged 
for such a time, that there is no reason to assume that 
these periods “have any limit, it makes no difference 
whether they are kept dry or in the mother liquid. ” 
It will be seen from a consideration of these facts how 
highly necessary it is, where possible, to destroy by 
burning all potato tubers infected with wet-rot, for to 
merely throw the creamy or watery mass on the ground 
is one of the most certain means of preserving the 
existence of the fungus. 
Bacilli, in the rod condition, are killed by drying, 
they cannot reproduce themselves in any dry place, or 
in, or on, any dry substance. They propagate in damp 
ill drained places and amongst wet and decaying refuse. 
The course to be taken by the practical potato grower, 
to prevent attacks from the Bacillus, is therefore 
