Die Parasiten der Infectionskrankheiten. 39 
be regarded as theoretical language, much less does it now seem 
to be merely theoretical in regard to the Texas Cattle Disease. 
Upon this subject we need only refer to the abstract of corre- 
spondence and of authenticated evidence in preceding sections of 
this report. In the States of Illionis and indiana, the proofs upon 
this point concerning the incubation or maturing of the excrement 
contagium during an interval of greater or less duration after it 
was dropped upon the ground, are so abundant and convincing, 
that many of the farmers seized upon the logical interpretation 
of their own peculiar experience and classes, and emphatically 
though somewhat rudely gave expression to this wonderful yet 
now easily understood doctrine, that Pettenkofer demonstrated 
when analyzing the history of cholera in Bavaria in the autumn 
of 1848. A vast quantity of evidence (experience and record) 
relating to this anomalous habit of the infective cause of the Te- 
xas Cattle Disease, is constantly coming into our hands, and it 
will in due time be analyzed and the results made public. 
5) Aid in elucidating important physiological and pathological 
questions connected wilh yellow fever. While summing up and 
analyzing the results of these investigations concerning the ,,Texas 
Cattle Disease“ we have been deeply interested in the contribution 
which these results make to practical knowledge of some of the 
most essential questions that have. in the past fifteen years, been 
started by physicians in the study of yellow fever. The compiler 
of this report having witnessed and professionally examined seve- 
ral hundred cases of this pestilence, and made dissections of 
nearly one hundred persons that died of it, was prepared to no- 
tice the points at which the results of the present investigations 
apply to the questions that have arisen in the study of yellow 
fever. In regard to these questions we will here notice the follo- 
wing points: | 
In 1853 Prof. Alonzo Clark, of New-York, discovered and 
described the characteristics of the fatty change and the peculiar 
coloration that occur in the liver in cases of yellow fever. He 
also described the nature and cause of the strange coloration 
which characterizes the liver in malignant remittent fever. Dr. 
T. H. Bache and Dr. Stewardson, of Philadelphia, made si- 
milar researches and reached similar results. The microscopical 
investigations by Dr. Lyon in the last epidemic of yellow fever 
in Lisbon, and similar studies by Dr. S. Fleet Speir, of Brooklyn, 
