DISEASES OF CULTIVATED PLANTS AND TREES 939 
nee We hear on all sides of the necessity for improved 
scientific methods of pol for the better understanding of 
plant-life and of the conditi necessary to secure the best 
culturist must be ready to act promptly on the first appearance 
of disease in his plants; he must work with both sword and 
1 in hand. 
hi 
infectious troubles such as wounds, injuries caused by frost and 
hail, by smoke and acid fumes in the atmosphere, and by the 
condone of the soil. He then describes the methods and 
perepre employed for checking or destroying infectious diseases, 
thus arrives at the subject of fungi, the chief cause of disea 
in viglants, as many of them are parasites on living plants and 
section, we learn of all the cases of disease ascribed to each class 
of fungi. A full it of host-plants serves as a further guide to 
the often bewildered student. 
T — than a compendium of the plant- oe 
occurring in all s of the world. Mr. Massee igen s his 
judgment to bear on many of the statements made: he ‘see bere 
accept Professor Percival’s account of Silver leaf disease on Plum 
destroy insect pests by infecting them with para ungi 
the other hand, he quite approves of the destruction of voles by 
means of a virus. The advice Mr. Massee gives is of practical 
wisdom and common sense: it may be to destroy a hopelessly 
diseased crop; to gather and destroy dead branches that carry on 
the mischief; to attend to the leaf-mould used in in potting, or to 
and save the plants by washing and spraying with fungi- 
ides. He always draws on his own great experience and sound 
observation. 
The question as to the increase of plant Re so often alleged 
in recent years, is also touched on. Mr. Massee finds that it is 
impossible to come to any definite conclusion on the matter. 
One aspect of the subject is poagoe = emphasized : that 
cultures. He remarks on the sirclant tos onan disease, C erco- 
spora melonis:— This epidemic may, in a sense, be | upon as 
an solar creation, inasmuch as it can only extend at a rapid 
rate under the modern conditions of culture.” And again under 
C. viole, tihick a = the 
