424 Degeneration of T. gamhiense 
impossible to distinguish between the normal trypanosomes and the 
large number of degenerating forms mixed up with them, and there¬ 
fore, at Professor Nuttall’s suggestion, an attempt has been made 
to trace some of the stages in the degeneration of this parasite. 
In order to ensure the degeneration of all the trypanosomes in 
the blood, drug treatment was employed. Seven hours after a 
subcutaneous injection of 1 c.c. of a 2 % solution of arsenophenylglycin 
into a heavily infected rat (the blood containing 60—80 parasites to a 
microscopic field) no parasites could be observed in the peripheral 
circulation, and so by making a series of films at short intervals 
between the time of injection and seven hours later, the various 
stages in the degeneration of the trypanosomes could be observed. 
It was also found that T. gamhiense degenerates very rapidly on being 
taken into the alimentary canal of Ornithodoros mouhata, and a second 
series of films was prepared from the contents of the gut of a tick 
which had previously been fed upon an infected animal, but the de¬ 
generation forms observed do not differ in any marked degree from 
those occurring in the blood of a rat after drug treatment. 
Technique. 
In all cases rats were the experimental animals employed because 
of the large number of trypanosomes occurring in the peripheral circula¬ 
tion. When the number of parasites in the blood of the infected animal 
had reached as high as 60—80 to the microscopic field, an injection 
of 1 c.c. of a 2 ®/o solution of arsenophenylglycin was administered 
subcutaneously, and films made from the blood of the rat at intervals 
of one hour. As a general rule the trypanosomes had disappeared 
from the circulation 6—7 hours after the injection and, therefore, films 
were only made during the first seven hours. 
Both the “ dry ” and “ wet ” methods of fixation were employed. In 
the former case the films were fixed in absolute alcohol and then stained 
either with Giemsa or Azur, the latter giving the better results, 
especially for demonstrating the axial filament. In the second case, the 
films were fixed in strong Flemming’s solution, and afterwards stained 
either with iron haematoxylin, or with safranin and methylene blue. 
(Salvin-Moore and Breinl, 1907.) 
For the study of the granules and the general form of the trypano¬ 
somes dry films were found to be the most useful, but for the finer 
details the wet films were far superior. 
