Last Work. Final Honors Y)1 



displacements occurring in tlic early lifc"^'' of tlic plants. His 

 final explanation of the "cysts" or "cavities in the pith, lined 

 by a well-defined small celled membrane," which he later dis- 

 covered, was that these were " the result of implantation of tiny 

 fragments of torus into the tissues under the torus." This was 

 the simplest explanation, he said, but also in his mind was the 

 question, '" may they not be the product of very young pith cells 

 abnormally stimulated.'* Their regularity would suggest this. If 

 the ray flowers out of the place were fertile," he commented, 

 " we might infer that they got an excess of nutrient substances, 

 but as they are sterile like the normal rays, we may suppose that 

 they are tubular flowers converted into sterile ray flowers through 

 some defect in nutrition." 



A theory of parasitism was also advanced. Along with his 

 potentiometer tests of inoculated plants that year to determine at 

 what day-and-night hours the maxima and minima readings for 

 pH and total acidity fall, he had been studying the influence of 

 light, among other environmental features, as a factor in the 

 stored acid content of tumors. He studied in other plants bud 

 germination and the interference of functions subserved in the 

 process by sugars and starch in various parts of young and old 

 plants. His memoir, " Tumors, cysts, pith bundles, and floral 

 proliferations in Helianthus," ^° covered special investigations 

 which lasted from 1924 through 1926; but the summary of his 

 results in his paper, " Changes of structure due to a modified 

 environment," reads: 



These results were first obtained by inoculating the crowngall organism 

 {Bacterium tutnefaciens) into young flower heads and so far this method 

 has given the most numerous and striking examples, but the same results, 

 exclusive of the supernumerary capitula, were obtained in a smaller number 

 of instances from simply dislocating tiny fragments of tissue of the recep- 

 tacle by means of repeated needle punctures. The results show that cysts 

 are independent of tumor formation, but in case of the bacterial inocula- 

 tions the walls of the cysts bore numerous tumors which were either discrete 

 or fused over long distances. These crowngalls frequently filled the cyst 

 cavity and stretched it, often rupturing its walls to appear on the surface 

 of the stem. My experiments were made in 1923-1924, and were repeated 



** Tumors, cysts, pith bundles, and floral proliferations, op. cii., summary. 



^"Smith's diar)' shows that lie wrote the memoir in 192'>. He may have bequn to 

 report his discoveries of 1924 to the Academy that year. Evidently a delay in pub- 

 lishing his paper enabled him to include his confirmatory results of 1926. 



20 



