98 
A Neiv Grerjarine 
Methods. 
The parasite was studied both alive and in stained preparations. 
Living forms were examined by drawing out the gut of the larva in a 
drop of normal salt solution and covering the preparation with a cover- 
slip. The gut was either left intact or it was purposely ruptured with 
the object of liberating the organisms it contained. It is useful some¬ 
times to substitute egg-albumin for the salt solution, as the coverslip 
does not then exert so much pressure on the gut, besides which the 
structure of the nucleus of the living parasite can be made out better 
in those forms which break out of the gut. 
The spores or cysts in the excreta were observed from day to day 
in situ ; they were also examined in egg-albumin or salt solution. The 
cysts were easily picked up on the point of a fine needle, especially if 
they were first covered with a little egcf-alburain. Useful information 
Fig. 1. Showing efiect of compressing a cyst. 
as to the structure of the parasite was often gained by compressing it, 
this being accomplished by abstracting, by means of filter-paper, a little 
of the medium from beneath the coverslip (see Fig. 1). Parasites killed 
with a drop of osmic acid solution, run under the coverslip, were 
specially favourable for the study of the myonemes. 
Generally for staining purposes the parasites were liberated from 
the gut in a small drop of albumin solution, in which they were 
transferred to corrosive-alcohol fixing fluid, being afterwards washed 
and stained. The cysts or spores in the exci’eta were treated in the same 
way. This method is excellent for such relatively large objects, which 
cannot be fixed to a slide by drying. In staining, the best results were 
obtained with Heidenhain’s iron-haematoxylin or Seidelin’s modification 
thereof. Sometimes Flemming’s fixative was used followed by the 
safranin-methylene-blue method of staining. 
The parasites and their cysts were also studied in sections. The 
whole gut was placed in a drop of albumin on a plate of paraffin. This 
was put whole into the fixing fluid, and it could be then manipulated 
with ease throughout the washing and embedding processes. 
