te 
preparation for a scientific career. Mathematics, as they are 
taught in France, habituate the mind to the grasp of general ideas 
and accustom it to rise from isolated facts to large generalisations. 
ve descriptive side o science, it cannot be doubted, has a 
mping influence, and it is the fate of too many of those who 
evo themse elves to it to be unable “to see the wood for the 
Cornu’s or Reamer studjes, at any rate, decided him 
the 
ir a S entiite career, and a « Ecole normale supérieure ” | 
eventually fixed on iy He was for a time assistant to 
e, professor at the Sorbonne, a man remarkable in many 
d the D mi sp ‘ 
moved to the Muséum as aide naturaliste to Brongniart, whose 
daughter he afterwards married. Brongniart brought down to 
our own day the best traditions of that illustrious school of 
French botanists whose philosophic insight into the principles of 
plant morphology and taxonemy-has probably never been rivalled, 
and certainly not a passed. 
Under Brongniart, Cornu devoted himself to mycology. He 
tye oe ina comparative brief gape a cag of papers, in 
ich one is a loss whether to admir ost the untiring 
‘hbeaiey: the ey © the wide range of his work. Every- 
thing pointed to his siti a foremost place in this branch of 
b But no one can be a mycologist SOE ai being drawn 
into t the study of plant diseases, in which fungi play s o large a 
part. Vegetable pathology e early attracted Outi: ie he did 
much excellent work in it. e owe to him the principle, now 
so familiar as to seem almost obvious, of preventive treatment by 
the careful destruction by burning of the débris of plants which 
may harbour r resting-s pores. 
In 1868 a mysterious disease made its appearance amongst the 
vines in the South of France. Planchon, the professor of botan 
at Montpellier (who owed his early training to Kew), discovered 
the cause in an insect—Phylloxera vastatriz—introduced from 
the New hal gee The injury which this rg gets inflicted on 
the principal cultural industry of France has been compared, and 
ag ese with pres to that of the Soa rade bas 8: w sees 
t Fra risen triumphant above this, ai 
ee was necessarily at once arent 1 in the ie fcaiese as it 
to enumerate the gid gicteacint positions in various inquiries which 
he filled ; the most important was that of “Secrétaire de la com- 
on académ mique du Phylloxera.” His memoir on the whole 
sabe published by the Academy has always seemed to me, for 
ree gga ess and finish, a model of what such a research ought 
Cornu became the acknowledged authority on the subject of 
the Phytioh ob: It had not been foreseen at first that the Sth 
