459 
NORMAL AND ABNORMAL MORPHOLOGY OF TRYPANO¬ 
SOMA LEW I SI, IN THE BLOOD OF THE RAT. 
By N. H. SWELLENGREBEL, Ph.D. 
Hygienic Imtitxite, University of Amsterdam. 
(With 15 Diagrams.) 
CONTENTS. 
PAGE 
1. Forms of the chronic infection ...... 459 
2. Stages of division ........ 466 
3. Abnormal morphology ........ 473 
4. Summary.477 
When comparing the results of the recent morphological study of 
T. leivisi, we note a general tendency to bring these observations into 
accordance with the views expressed in Schaudinn’s well-known publica¬ 
tion ^1904). In this paper I propose to discuss the morphology of this 
interesting flagellate under normal and morbid conditions, and to 
consider whether the present tendency to adopt Schaudinn’s views is 
justified. Since I shall take occasion to compare my observations with 
those of other authors, it will not be necessary to give a historical review 
of the subject. A full list of references will be found in the papers of 
Rabinowitsch and Kempner (1899), Wasielewski and Senn (1900), 
Laveran and Mesnil (1901), and Prowazek (1905). I have discussed 
matters of technique in a previous paper (1910) to which the reader 
may refer. 
1. Forms of the chronic infection. 
As is well known these forms appear 8—13 days after infection, they 
no longer divide. It is not necessary to insist on the general aspect, 
this being well-known from the description of the authors already 
Parasitology iii 30 
