442 
morphology of these organisms are as yet but little understood 
Information upon these matters, as well as upon the various lifecycles 
they appear to present, is greatly t.1 be desired Especially is this the 
case with regard to their morphology. The numerous descriptions of 
their structure and their metamorphoses already in existence have 
been drawn in general from the results of methods of research not 
calculated to produce any correct appreciation of their true cytological 
features. With very few exceptions, the study of the structure of the 
trypanosomes has been based, cither upon what can be made out of 
the live animals, or else upon observations made upon material after 
it has been heated and dried, a method which, to say the least of it, 
may be shown, so far .is the finer details of any cell structure are 
concerned, to be particularly barbarous. 
Trypanosomes, like other unicellular organisms, can, however, be 
fixed m a great variety of ways which are commonly used during 
cytological research. Hie chief manipulative difficulty 1 1 icv present 
is the unreadiness with which they can be made to take any sort 
of differential stain. Still this difficulty is not insurmountable; and 
ordinary preparations may be produced which stain as completely as 
can be desired. 
We have used the following fixatives .-—Fleming’s fl« ic 
sublimate acetic acid ; osmic acid vapour ; osmic acetic acid vapow 
and formalin vapour. 
When the animals have been fixed, it is in all cases des,table 
use somewhat spec.ai precautions in relation to the stain which t* 
Dri'nr i° t e "! ployed ' the P r °cess adopted depending upon tl 
are ! ° f “PP'yng a mordant, or mordants, before the actual s« ir 
FlemtoU fl h • the Wh ° Ie ’ WC haVe f ° Und that ^ fixa,ion "* 
of vTe?wh T UnqUest,onab,y rt- best from a morphological f* 
the sharpest ^ methods trough which we have obtain* 
safrantrin at T, haVC bee ”' ^ hand, the 
Appendix II " e ™ ethyIenc blue atain invented by Breinl (** 
iron h" “ato T ° ' 3 S%ht modifi -tio„ of the Heid^” 
iron haematoxylm process (see Appendix II) 
which 5 wTu a b r : StTitf.!® 1 ' (and in p- b *< 
is necessary i n the first il ' d,fferent s P ecific {o ^\ e 
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