406 THE CANADIAN NATURALIST. [Vol. X. 



taken him specimens of various sorts, and among them a mass of Pec- 

 tinatella, which I had found in an old suhmerged barge near the 

 mouth of the Humber. I remember tlie fact very distinctly, as it was 

 the first specimen of Pectinatella which I had found near Toronto, 

 and Professor Hincks took a great interest in it, as he had not met 

 with any fresh-water Polyzoa in Canada. Could this have been the 

 specimen ? It is a curious coincidence, to say the least, and perhaps 

 in a look through the Museum of the University the specimen might 

 be found, and the statoblasts would be sufiicient to decide the ques- 

 tion. Professor Hincks gives a sketch of the lophophore and it is hard 

 to think that he could have been mistaken as he was an unusually 

 skilful observer. The submerged barge was for many years a favorite 

 collecting ground, and in some seasons Pectinatella was very abun- 

 dant in the quiet water inside of it. 



ON CERTAIN PARASITES IN THE BLOOD OF THE 



FROG.^=^ 



By William Osler, M.D., M.E.C.P., Lond. 



Fellow of the Royal Microscopical Society of London. President of the Micro- 

 scopical Society of Montreal, Professor of the Institutes of Medicine, 

 McGrill University. 



In my Practical Histology class, during the winter of 1881-82, 

 while the students were working at the blood of the frog 

 (Rana Mugiens), 1 noticed in one of the slides a remarkable 

 body like a flagellate infusorian. I thought that it was one 

 which had got into the blood at the time of withdrawal, from the 

 water on the web of the foot. Meeting with examples in the 

 slides of several other students, my attention was again directed 

 to it, and I made several sketches and wrote down the following 

 description : — " Finely granular protoplasmic body, somewhat 

 triangular in shape, about the size of a colorless corpuscle. The 

 narrow end is prolonged into a cilium, while the other presents 

 a broad band of rapidly undulating protoplism, which at one 

 angle is prolonged into a long lash-like process. The un- 

 dulating fringe and the cilia are in constant motion, giving 

 the appearance of rapid waves passing from one corner to the 

 other, the waves of protoplasm gradually increasing in length 

 and tenuity until they have the appearance of projecting cilia. 



* Read before the Montreal Microscopical Society. 



