4o8 GENERAL PLANT PATHOLOGY 



becomes familiar with the gross anatomy, as well as the microscopic. 

 Photomicrographs can be made readily by the use of the Edinger appara- 

 tus which has been used successfully at the University of Pennsylvania 

 in class work. It adds materially to the interest of the work to take 

 photographs of the sections studied and make permanent prints of the 

 diseased structures. After a few years, the alcoholic stock material 

 will have increased to such an extent that all phases of pathologic 

 plant anatomy can be demonstrated, not only by actual specimens, 

 but also by sections. The sections, if made directly by the sliding 

 microtome, can be kept in large numbers in small bottles in 50 per 

 cent, alcohol, where they are available for class use at any time. The 

 paraffin mounts can be kept in block form ready for use when required 

 by the sequence of laboratory exercises and lectures. If alcohol is not 

 available on account of its high price, other materials may be used in its 

 place. 



The sections and alcoholic material having been prepared for use 

 can be studied for hypertrophy, for metaplasia, hypoplasia and other 

 pathologic conditions. Such an investigation presupposes a thorough 

 grounding in the technique of plant anatomy and histology, so that no 

 time may be wasted in unnecessary explanations. From the stand- 

 point of curriculum, such a course in mycology and pathologic plant 

 anatomy should be given in the junior, or senior years, or deferred until 

 the post-graduate years because of the special nature of the work. 



Written reports should be required of all students based upon the 

 experiments with the inoculation and infection of various cultivated 

 plants and their reaction to various fungi. Similarly, where pathologic 

 anatomy and histology of plant organs and tissues are concerned photo- 

 graphic prints may take the place of microscopic drawings. Each 

 topic considered in the lecture course should receive attention in the 

 laboratory and in the field and indoor experiments, because this work 

 is designed to prepare future plant doctors, teachers and investigators, 

 who are interested in the science of phytopathology and who are 

 anxious to be proficient in the study of plant diseases. 



Stock material should be kept of all the more common insect and 

 fungous diseases of cultivated and wild plants not only for such patho- 

 logic study, but also for a systematic and morphologic work with insect 

 and fungous parasites. The mycologic student should be able to 

 identify not only the more common insects and fungi after such a 



