For the cultivation of such parasites, e.g. Trypanosomes, haemospiridia, etc., a number of different nutrient media have been recommended from time to time. The methods of Nony and McNeal, Lewis and Williams, Laveran and Mesnil, Rabinowitsch, etc., have all been intensively employed and have given fair results. The majority of these methods were tried in the laboratory but eventually, it was found that by the use of "broth", excellent preparations could be obtained revealing the extra-corporeal existence and development of these, and other similar parasites.
In the case of parasites of the frog, the difficulty, up to the present, has been the presence of bacteria of contamination, which upsets the growth of the parasites under consideration. In order to avoid this, the greatest of technical care must be exercised. It matters but little if those intra-corpuscular bacteria - namely the Cytamoebae bacterifera -