238 Trypanosoma lewisi 
TABLE II. 
Dimensions 
Standard pre¬ 
paration, own 
observation 
Standard pre¬ 
paration, after 
Minchin 
Corrosive 
alcohol 
o 
CM 
o 
& 
3 
c/3 
o 
Alcohol, dried 
films 
Alcohol, wet 
films 
Rath’s liquid 
Hermann’s 
liquid 
Flemming’s 
liquid 
Post-nuclear 
2-6 
4-5 
2-4 
2-6 
2-5 
1-8 
2-2 
2-6 
2-9 
Intranuclear 
8 - o 
12-22 
8-4 
9-8 
10-7 
8T 
10-6 
8-7 
7-9 
Prenuclear 
4-0 
7-04 
4-7 
5-6 
6-8 
3-2 
5'5 
4-7 
3-8 
Greatest breadth 
1-6 
1-04 
IT 
1-6 
1-7 
1-5 
1-5 
1-8 
2-2 
Whole length 
15 T 
23-8 
15-5 
18-0 
20-0 
13-1 
18-3 
16-0 
14-6 
Concluding remarks. 
The 
opinion 
generally accepted 
at present, 
that the old method of fixing and staining is misleading when used for 
the study of minute cytological details, is incorrect with regard to Try¬ 
panosoma lewisi. This method is at least equivalent to the best 
methods of wet fixation and gives, followed by Giemsa’s stain, a 
differentiation of the structure of nucleus and blepharoplast which 
is decidedly superior to Heidenhain’s stain, if only overstaining is 
prevented. Consequently the papers referring to Tr. lewisi , issued 
before 1907 and based on the old fixing and staining methods, are fairly 
reliable. Of course this statement holds good only for Tr. lewisi ; with 
other haemoflagellates, especially the larger ones, things may be different 
as may be concluded from M. Robertson’s description (1909). 
It will be advisable when studying hematozoa to use first of all the 
method of dry fixation with subsequent staining by Giemsa’s method. 
Of course it is always advisable not to be content with one method but 
to test the results of it by others; but to reject the old method as 
untrustworthy is wholly unjustifiable and would mean a great loss for 
microscopical technique. 
REFERENCES. 
Braun and Luhe (1909). Leitfaden filr Parasitologische Untersuchungen. 
Doflein (1909). Lehrbuch der Protozoenkunde. 
Gismsa (19Q9). Deutsche rued. Wochenschr. No. 40. 
Heidenhain (1907). Plasma und Zelle. 
Minchin (1909). Quart. Journ. micr. Science , Vol. liii. 
Moore, Breinl and Hindle (1908). Annals of Prop. Med. and Parasitol. 
Vol. ii. 
Prowazek (1905). Arb. Kaiserl. Ges.-Amte. Vol. xxii. 
Robertson (1909). Quart. Journ. micr. Sci. Vol. liii. 
Rosenbusch (1909i. Arcliiv f. Protistenkunde, Vol. xv. 
Wenyon (1908). Third Report Wellcome Research Laboratories. 
