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OBSERVATIONS ON LEECHES. 
ART. LXXVII.— OBSERVATIONS ON LEECHES. 
By Otto KohiNke. 
In consequence of the premium offered by the French 
Society for the Encouragement of Arts, in the year 1840, 
for the best observations on leeches, the most advantageous 
methods of rendering them fit for frequent use, and for mul- 
tiplying them in artificial ponds, I was induced to make the 
following experiments : — 
Every one who has had much to do with the treatment of 
leeches will be aware of the great trouble and care required 
to render them serviceable a second time. I have succeeded 
in making them fit for use three, four, and even five times, 
by a method which I am not aware has hitherto been em- 
ployed. The results of my experiments I will communicate 
in the present article. 
In these experiments different species of leeches were em- 
ployed, for instance — 
Sanguisuga interrupta, M. T. 
Sanguisuga officinalis, Savig. 
Sanguisuga medicinalis, Savig. 
which are described in every good work on zoology. 
S. medicinalis was obtained from Jutland, where it still 
occurs in plenty. 
The treatment was as follows : — Each kind was kept in 
an open wooden jar, containing a sufficient quantity of water 
and some fresh plants of Calamus. The border was rubbed 
in on the interior for two inches with dilute sulphuric acid. 
As soon as the leeches had been employed they were thrown 
into a vessel in which were placed some beech-wood ashes; 
in a very short time they had vomited all the blood, and 
were then removed as quickly as possible, in order not to 
weaken them too much, on to a seive, and well washed ; and 
