924 The American Naturalist. [November, 
has been in contact with a diseased plant, at least not until it 
has been disinfected. 
There is another point to which the author desires to call 
special attention, viz., to the removal of leaves which begin to 
show signs of the disease at the tip. On May 20, 1883, the 
diseased leaves were entirely cut away from seventeen hyacinth 
plants. On September 26th, sixteen of these bulbs were entirely 
sound, although rather small. The other bulb was entirely 
decayed ; but from what cause, it was no longer possible to 
determine. Planted in pots these sixteen bulbs blossomed in 
April, 1884. The following June they were dug up once more, 
and on cutting them open all were found to be sound. This 
experiment was tried on many other bulbs, and always with 
the same success. It was also tried by several horticulturists 
in their fields with results entirely confirmatory. It is, there- 
fore, certain that the bulb can be preserved by the judicious 
removal of diseased leaves. 
Since the bacteria have always penetrated much further into 
the leaf than is to be seen with the naked eye, the whole leaf 
should be removed even when only slightly attacked. The 
frequent complaint that cutting off the diseased parts does no 
good, shows that not enough attention has been paid to this. 
Of course, when the bulb is already infected, cutting oft the 
leaves amounts to nothing (1). 
Finally, it goes without saying that the debris of diseased 
hyacinths should not be left in the field or near it, as one might 
be tempted to do on account of its value for manurial purposes. 
All such debris should be thrown into a deep ditch and disin- 
fected with quick lime. 
Remark.—Considering the time when this piece of work was 
done, it is remarkably good, and in all of the papers cited 
the internal evidence indicates a careful, conscientious, bril- 
liant investigator. There can be no doubt that the disease 
is due to a bacterial parasite; but to complete the proof that 
the disease is due to the specified organism it should be obtained 
by infections with pure cultures obtained from single colonies. 
The organism thus isolated should also be studied under a 
wider range of artificial conditions than were employed. 
Indeed, excluding the pathogenic test, it is more than doubtful © 
if the organism could be identified from the description. 
