19 
Report of the Laboratory of Comparative 
Pathology for the Year Ending 
February 28, 1922. 
The laboratory can report for the past twelvemonth a 
very interesting and perhaps practically valuable ex- 
perience. During the course of routine examinations a 
number of instructive cases have been encountered 
while some of the experimental and investigative work 
that has been under way has reached a point of readiness 
for publication as well as for direct clinical trial. Most 
of this latter is technical in nature, for which reason a 
full discussion will be reserved for Part II of this report, 
although certain general phases of it may be touched 
upon in this section. 
Following the usual custom I wish to report first upon 
the general mortality of mammals and birds. There 
were 2134 specimens of these classes in the collection 
during the year, of which 520 died, a percentage of 24.4, 
or slightly in excess of that for last year. Analysis of 
our records does not offer any ready explanation for this 
increase except for the deaths in a few orders, the figures 
Mammalia 
AND AVES 
Mammalia 
Aves 
For the Year 
Ending 
Ani- 
Per 
Ani- 
Per 
Ani- 
Per 
mals 
Deaths 
cent. 
mals 
Deaths 
cent. 
mals 
Deaths 
cent. 
exhib- 
mor- 
exhib- 
mor- 
exhib- 
mor- 
ited 
tality 
ited 
tality 
ited 
tality 
February 28, 1907 
1343 
346 
25.7 
521 
109 
20.9 
822 
237 
28.8 
February 28, 1908 
1439 
275 
19.1 
487 
84 
17.2 
952 
191 
20.0 
February 28, 1909 
1439 
267 
18.5 
487 
98 
20.1 
952 
169 
15.6 
February 28, 1910 
1412 
250 
17.7 
479 
90 
19.2 
933 
160 
17.1 
February 28, 1911 
1467 
318 
21.6 
500 
93 
18.6 
967 
225 
23.2 
February 28, 1912 
1513 
360 
23.7 
516 
105 
20.3 
997 
255 
25.5 
February 28, 1913 
1511 
309 
20.5 
552 
124 
22.4 
959 
185 
19.2 
February 28, 1914 
1543 
290 
18.9 
554 
98 
17.6 
989 
192 
19.5 
February 28, 1915 
1614 
347 
21.5 
562 
104 
18.4 
1052 
243 
23. 
February 28, 1916 
1630 
381 
23.3 
601 
108 
17.9 
1029 
273 
26.5 
February 28, 1917 
1888 
337 
18.1 
596 
90 
16.7 
1292 
247 
19.1 
February 28, 1918 
2019 
451 
22.3 
629 
92 
14.6 
1390 
359 
25.8 
February 28, 1919 
2020 
370 
18.3 
648 
114 
17.5 
1372 
256 
18.6 
February 28, 1920 
2033 
447 
21.9 
628 
147 
23.3 
1405 
300 
21.3 
February 28, 1921 
2390 
574 
24. 
671 
126 
18.7 
1719 
448 
26. 
February 28, 1922 
2133 
520 
24.4 
611 
121 
19.8 
1522 
399 
26.2 
Since only a few of the reptiles and amphibians are autopsied they have been sub- 
tracted from the death list and the percentage computed on basis of mammals and birds 
only. 
