Placi;d ox a Nation-wiih Basis 189 



studies of a fungous disease and one of supposed bacterial origin. 

 Several years later J. B. S. Norton, searching the second rather than 

 first season of the fungus, found the Sclerotinial or perfect form 

 of the Monilia, st)mething for which Smith searched "in vain."'"* 



During the spring of 1889, Smith gathered bark specimens 

 showing a brown spot, of a tree badly diseased with yellows, 

 from an orchard in Delaware. Preserving the material in picric 

 acid, he determined to infiltrate and imbed it in paraffin for section 

 cutting and examination according to a method of Dr. J. W. Moll 

 abbut which he had read in the Botanical Gazette.-^ Five and a 

 half pages of quo'ted notes had been culled from this article and 

 copied into his " Record Book of Culture Media." 



The superior staining procedures applied in animal pathology 

 were making possible searching inquiries into the smaller bacteria 

 and higher fungi. But the technological advancements in the study 

 of plants were still slow. A dozen or more years had passed 

 since Weigert, Paul Iihrlich, and others had begun to utilize 

 anilin stains to demonstrate bacteria in animal tissues. Plant 

 scientists, however, were slower to ascertain the "best methods" 

 to stain bacteria in vegetable tissues. In 1905 ^° Smith suggested 

 as a reason the difficulty inherent in "the fact that the tissues of 

 the higher plants often take the basic anilin stains as readily as 

 the bacteria and retain them even more tenaciously." 



Several hundred examinations of stained and unstained ma- 

 terials, made by Smith between November 15, 1889 and February 

 15, 1890, resulted in "only negative results. No fungi and no 

 bacteria could be discovered. Part of the sections," Smith ex- 

 plained, " w^ere infiltrated, embedded, and cut on the microtome. 

 The microscope used in all these examinations was Zeiss stature I, 

 Oculars 2, 4, and 8 (22.5 mm) and 18. (10 mm). Objectives AA. 

 D. F. and Aprochromatic 3 mm. Homag. in Apert. 1.30. Stand 

 with Abbe condenser." It was plainly disappointing that sections 

 cut through and in the vicinity of the small brown spot of the 

 bark, though infiltrated and paraflin-embedded according to Dr. 

 Moll's method, revealed no parasite. 



February 17, Smith began another month of experiments. A 

 section, stained three days in Haematoxylin according to a formula 



■^ Fifty years of pathology, op. cit., 28. The year of Norton's discovery was 1902. 



" 13: 5, Jan. 1888. 



^'' Bacteria in relation to plant diseases, op. cit., 1: 29. 



