PREFACE AND ACKNOWLEDGMENTS. 
Working Party No. 2, Yellow Fever Institute, consisting of Passed 
Asst. Surg. Herman B. Parker, Asst. Surg. Edward Francis and Act¬ 
ing Asst. Surg. George E. Beyer, was detailed by the Surgeon- 
General U. S. Public Health and Marine-Hospital Service, with the 
approval of the Secretary of the Treasury, to Vera Cruz, Mexico, 
April 27, 1903, for the purpose of making further studies upon the 
cause and methods of transmission of yellow fever. 
Doctor Parker returned to Washington upon official business June 
7,1903, and on September 13,1903, returned to Vera Cruz with Passed 
Asst. Surg. M. J. Rosenau, Director of the Hygienic Laboratory, who 
had in the meantime been appointed chairman of the commission, 
with instructions to repeat that part of the work of Working Party 
No. 1 relating to the Myxococcidium stegomyice. 
Professor Beyer left for New Orleans on October 4 to resume his 
duties at the Tulane University of Louisiana. 
The remaining three members of the working party continued work 
at Vera Cruz until November 28, 1903, when, on account of the sub¬ 
sidence of the yellow fever epidemic and scarcity of material, they 
returned to Washington. 
The commission made a brief report to the Surgeon-General, signed 
by all of its members and published in the Public Health Reports 
for January 15, 1904, as follows: 
Findings of Working Party No. 1, Yellow Fever Institute, not all corroborated 
by Working Party No. 2. 
Washington, December 18, 1903. 
Surgeon-General. 
Sir : We have the honor to report that, as a result of our studies at Vera 
Cruz, Mexico, this summer, we have not been able to corroborate all the findings 
of Working Party No. 1, Yellow Fever Institute, Public Health and Marine- 
Hospital Service, having found phases of the organism described by them as 
Myxococcidium stegomyiav in normal mosquitoes. 
Respectfully, M. J. Rosenau, 
Chairman Working Party No. 2. 
H. B. Parker, 
Edward Francis, 
Geo. E. Beyer. 
The commission was now, January 18, 1904, dissolved, and its 
members permitted to publish individually any further matter bear¬ 
ing on the summer’s work. 
This bulletin, therefore, has been prepared by two members of the 
commission, Doctors Rosenau and Francis, who have continued cer¬ 
tain phases of the work, but who here wish to make full acknowledg- 
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