length. Richard has several times seen the fully developed parasite emerge from its ‘shell’—the remnant of the invaded red corpuscle—to which it may remain attached, and which can only be seen with great difficulty. Sometimes only the motile filaments penetrate the envelope in which the body of the parasite remains inclosed. In both cases the filament is seen to undergo active movements, and when its extremity is caught in the fibrinous reticulum the body itself oscillates. This movement may last for an hour. Usually, however, no movement is observed, and the corpuscles containing very small parasites never move. The infected corpuscles become disorganized, the pigmentary collarette is broken down, and a grayish mass inclosing some black granules remains. The pigment granules when set free are rapidly picked up by the leucocytes; the melaniferous leucocytes are therefore epiphenomena."
Commenting upon the observations of Laveran and Richard, I say, in the work just referred to:
"We can not doubt that a true account has been given of what the observers believe they have seen. But there is a wide field for doubt as to the deductions made from the various observations recorded; for in microscopical studies of the blood made with high powers there is a great liability to error and to misinterpretation of what is seen. We may question, for example, whether the belief of Laveran and Richard that the appearances noted by them are due to parasitic invasion of the blood-corpuscles is well founded, without calling in question the accuracy of their observations."
At the time this was written pathologists generally were not disposed to attach much importance to the alleged discovery of Laveran, and this was especially true in Germany and in those countries in which physicians were in the habit of awaiting the verdict of German bacteriologists before accepting anew "disease germ." One reason for this failure to give proper consideration to the discovery of Laveran was the fact that there was a rival in the field. A year before the publication of Laveran's paper, giving an account of his observations, the distinguished German pathologist Klebs, in association with the prominent Italian physician Tommasi-Crudeli, had announced the discovery of a bacillus which they believed to be the cause of the malarial fevers, and which they named Bacillus malariœ. Their experimental investigation was made in Rome with material obtained from the malarious marshes in the vicinity of that city.
The evidence offered in the original memoir of Klebs and Tommasi-Crudeli in favor of the view that the bacillus described by them is the cause of malarial fevers in man, is derived from experiments made upon rabbits, in which culture
