142 The American Naturalist. [February, 
much entitled to recognition as those whose origin we do not happen 
to know.—CHARLES E. Bessey. 
Prillieux’s Diseases of Plants.’ —Among recent contributions 
to botanical literature is the first volume of a work on the diseases of 
agricultural plants including forest and fruit trees by Ed. Prillieux, Pro- 
fessor in the (“ Institut National Agronomique,” Paris). The work is 
the outcome of the author’s twenty years study and teaching of Eco- 
nomic Vegetable Pathology. 
In the introduction the change in the methods of viewing plant dis- 
eases is referred to. Instead of trying to trace an anology between 
human pathology and phytopathology, plant diseases came to be re- 
garded as due to changes of normal physiological functions produced 
either by unfavorable conditions or by the action of parasitic organisms 
penetrating the tissues. The placing of phytopathology on a more 
rational basis is attributed to De Candolle.’ In this connection Unger‘ 
might well have been cited. 
The author next speaks of the aims and purposes of the work. He 
says: “If I am able to render the study interesting and intelligible to 
agriculturists and to all persons living in the country who have received 
some general knowledge of the structure of plants, I shall have obtained 
the end I have in view.” 
In speaking of the difficulties of studying minute parasitic plants he 
adds: “It seems to be established that such researches present too 
many difficulties to be carried on by any one who wishes. My great- 
est desire is to dissipate this belief and to facilitate the beginnings of 
observers who, living in the country, are able to test on cultivated 
plants the facts already observed and described, and to examine the 
parasites in quantity in all their stages of development. If they ac 
quire a taste for these oe they may be able in their turn to add 
many new facts to science.” We believe the many acute investigators 
who after thorough equipment have spent years in trying to solve some 
of the problems presented by plant diseases will not think us pessi- 
mistic if we venture to predict that the author’s hopes regarding the 
contributions to the life histories of parasitic fungi which he expects 
from the novice will not be realized. If, however, he succeeds in get 
ting the intelligent farmers to observe carefully the parasitic plants 
? Prillieux, Ed. Maladies des Plantes Agricoles et des Arbres fruitiers et Forest- 
ders causées par des parasites végétaux. Home Premier, Paris, 1895. 
3 De Candolle, Aug.-Pyr. Physiologie Végétale. Paris, 1832. 
* Unger, Franz. Die Exantheme der Pflanzen. Wien, 1833. 
