182 Investigations in Plant Pathology 



the Department at Washington what he believed of the progress 

 of the work. Henry was surprised that the disease had spread over 

 so large an area in so short a space of time. Vine growers in Los 

 Angeles and Orange counties were desolate, and discouragement 

 pervaded all viticultural regions. He found Pierce devoting him- 

 self most enthusiastically to his task and possessed of "' a great 

 deal of ability for this line of investigation." "As before noted, 

 we found signs of the disease in every vineyard, though the attack 

 is very recent," Henry reported. 



Wherever we went, as soon as the people learned the objects of our 

 visit they gathered about us and asked many questions, all parties showing 

 deep interest and great anxiety, hi cases as soon as they were informed that 

 the disease seemed to be present., the next question was if the agent had 

 found a remedy. Naturally enough they care little for the name or history 

 of the disease; all they want to know is how to cure it. 



In the light of modern knowledge, this disease, like peach 

 yellows, has been shown to be caused by a virus which is trans- 

 mitted by a leaf-hopper. The importance of Pierce's investigations 

 lies more in the evolution of field and laboratory technological 

 research than in the immediate consequence of his discoveries. 

 In his study of this disease, his exclusion of parasitic fungi as 

 causes, his examination of the possible connection of insects and 

 worms to the malady, his find of "bacteria-like bodies (AI/- 

 crococi?) in large numbers within the chlorophyllose cells of the 

 spongy parenchyma immediately surrounding the spiral vessels 

 supplying that region," and other of his proofs and procedures 

 were in keeping with the best laboratory practice, and reveal the 

 quality of his preparation at the University of Michigan. While 

 most of his study was performed at Santa Ana, some of the work 

 was sent to Washington. 



That year work facilities of the Section of Vegetable Pathology 

 in the large red brick building of the Department of Agriculture 

 at Washington had been expanded. More room, some of it attic 

 or garret space, had been made over into small laboratories, and 

 improved apparatus had been procured. Galloway announced in 

 his 1889 report: 



A bacteriological laboratory v.'ith all the modern improvements has been 

 fitted up, thus enabling us to greatly extend our field of research. A small 

 green-house has also been purchased and has proved very useful. For the 



