PREFA CE 



THE results which Dr. J. Cedric Carter 

 reports in this article of the Bulletin 

 OF THE Illinois Natural History Survey 

 are the outcome of six consecutive years, 

 1939 through 1944, of study in the field, 

 greenhouse and laboratory of a complex of 

 disease manifestations in the American elm. 

 The elements of this complex, singly and in 

 /arious combinations, have puzzled both 

 practical and scientific tree experts for many 

 .ears. 



Dr. Carter has demonstrated that there 

 s a direct relationship between an obscure 

 lisease of the heartwood of living elms, 

 :ommonly called wetwood, and certain 

 orms of twig and branch dieback, "bleed- 

 ng" from crotches and wounds, and the 

 wo conditions known to tree experts as 

 nternal slime flux and external slime flux. 

 !4e has isolated a species of bacterium, 

 ipparently heretofore undescribed and un- 

 lamed, which can produce elements of this 

 lisease complex upon being inoculated into 

 lealthy trees. 



Although supporting material and ob- 

 ervations were gathered in many places in 

 Uinois, the major part of the field work 

 onnected with this investigation was done 

 n the Village of Hinsdale, in Du Page 

 "ounty, Illinois. Much of the equipment 

 lecessary for some of the studies and certain 

 'materials, such as fertilizers, were furnished 

 y the Village, along with labor and other 

 ;elp, as occasion demanded. Many of the 

 lustrations in this paper show phases of 

 'lese Hinsdale studies. 

 Mr. Robert S. Hopkins, Commissioner 



of Public Works for the V'illage, furthered 

 the work in all possible ways. With his 

 approval, Mr. William Ellsworth Rose, as 

 Forester, took an enthusiastic interest in 

 the work from 1939 through 1941, and Mr. 

 Joseph F. Shafer, Assistant Commissioner 

 of Public Works, showed an equal interest 

 from 1942 through 1944. These men gave 

 generously of their time, assisting personally 

 and assigning men employed under them to 

 various tasks as need arose. Among such 

 tasks may be mentioned the collecting of 

 wood, gas and sap samples for laboratory 

 testing, the felling and cutting up of certain 

 trees, the periodical recording through 2 

 years of the readings of gauges installed in 

 trees, the feeding of several trees and the 

 setting up of a number of experiments. 

 Also, through their reports to the Village 

 President and Board of Trustees, Mr. Rose 

 and Mr. Shafer kept the officials and 

 citizens of Hinsdale informed regarding the 

 progress of the investigation. 



To acknowledge all of this help is a 

 pleasure. The elements of personal and 

 public interest did much to make Dr. 

 Carter's study complete and exact in many 

 details. Moreover, the cooperation between 

 officials, of the Village of Hinsdale and 

 scientists of the Illinois Natural History 

 Survey, cordially maintained throughout, 

 provides an example showing how com- 

 munities in Illinois can proceed toward the 

 solution of tree problems requiring the 

 services of highly specialized scientists. 



T. H. J'RisoN, Chief 



Illinois Natural History Survey. 



