6 PREFACE BY TRANSLATOR. 
been seen by the investigator. The commission sent to 
Havana last summer for the investigation of yellow- 
fever, was instructed to pursue this method, and was 
accompanied by a photographer and supplied with all 
the necessary appliances for carrying these instructions 
into effect. 
The superficial reader may find much to criticise in 
the work of Dr. Magnin, but I am convinced that 
those who read it carefully cannot fail to be pleased 
with the truly scientific spirit in which it is written; 
the fairness with which conflicting opinions are stated ; 
the caution manifested as to the drawing of definité 
conclusions where questions are still under discussion ; 
and, above all, the extent of his literary researches and 
the systematic way in which he has arranged the re- 
sults. 
For the naturalist, for the physician, or for the non- 
professional man of general culture, who desires to have 
accessible in a condensed form the most important re- 
sults achieved in this line of inquiry up to the present 
day, this volume cannot fail to be of value; while for 
the student and the investigator in search of fuller 
information, the summary given of the labors of nu- 
merous individuals, together with the copious bibliog: 
raphy, which I have brought up to date, will doubtless 
be of service. Believing this to be true, it has been a 
pleasure for me to devote a portion of my summer vaca- 
tion to the translation of this httle volume. 
G. M. &. 
Sarem, Mass., August 1, 1880. 
