OBSERVATIONS ON LEECHES. 
309 
after having undergone this treatment they were conveyed 
into a vessel containing water, and coarsely-pounded, well- 
washed charcoal, and here left for the space of twelve hours, 
upon which they were removed into the above-mentioned 
jars. 
In this manner I obtained with 180 leeches (60 of each 
kind) the following results : — I may observe that they were 
employed at intervals of from three to four weeks, from July 
to October of the same year. 
S. interrupta. 
Leeches Number which 
employed, died in the interval. Observations. 
1st time 
60 
7 
The first time 2 would 
2d 
a 
53 
31 
not suck, the second time 
3rd 
a 
22 
14 
5, and the fourth time 3, 
4th 
a 
8 
after which the remain- 
der died within 8 days. 
s. 
officinalis. 
Hungarian Leech. 
1st 
time 
60 
9 
The second time 3 
2d 
« 
51 
37 
would not suck, the third 
3rd 
u 
14 
10 
time 2, and the fourth 
4th 
(6 
4 
time 1, the remainder 
died within 19 days. 
S. medicinalis. 
1st time 
60 
4 
The first time 1 would 
2d 
a 
56 
18 
not bite, the second time 
3rd 
Ci 
38 
19 
6, and the fourth time 7, 
4th 
a 
19 
10 
the remainder all died 
5th 
u 
3 
within 5 days. 
From these results Sanguisuga medicinalis would seem 
to deserve the preference, but the shortness of the transport 
may perhaps account for this considerable difference. 
Other experiments have at the same time taught me that 
when the leeches are employed only at intervals of from 
eight to ten weeks they preserve far better. 
