216 
parently well and comfortable. — For the purpose of finding the 
animals I employ quite flat glass-cups of c. 20 ctm. in diameter. 
Here I pour water over the material and spread it over the cup. 
It is not convenient to have too much of earth as it renders the 
searching for the animals difficult; it is not easy especially to search 
in fatty mould and clayey material. 'The glass-cup is placed on a 
black underlayer, raised a little over it, on the turned cover of a 
Petri-cup and then I begin the search by means of a good 
lens. The animals are taken with a very fine needle — for the 
smallest forms a pipette is employed, drawn out in a long fine 
tip — and placed in a watch-glass with some water. From here 
they are picked up and placed one by one on a slide for examina- 
tion. Many of them being very agile — in that respect the various 
species behave most differently — it is necessary to make them 
immobile, and this is generally done by holding the slide for a 
moment cautiously over a small spirit-flame; thereafter the cover- 
slip is applied. which must be supported by wax or the like. 
If these animals are to be prepared for study or for Museum 
use it is preferable to mount them on slides on account of their 
diminutiveness. Several fluids are recommended for fixation. De 
Man employes a mixture of Glycerine 3 and acetic acid 1/3. 
I have not succeeded in employing this and others have had the. 
same misfortune; Orley thus says in his paper: ,,Die Rhabditiden 
und ihre medicinische Bedeutung", that ,,solche Pråparate sehr auf- 
hellen und schrumpfen". Jågerskjåld recommends in his paper 
of 1901: ,,Weitere Beitråge zur Kenntniss der Nematoden" a mixture 
of Alcohol 50 %/0, 70—90, Glycerine, c. 30—70 and glacial acetic 
acid, c. one drop. Loos recommends mixtures of a similar com- 
position (Zool. Anz. 1901) and Orley employs picro-sulphuric, 
solution of corrosive sublimate and !/4 per cent solution of osmic 
acid, — 
I have tried for my preparations most of these reagents with 
unequal results and moreover I have tried a number of other mix- 
tures which I thought might be employed with success. These 
