96 
Haemoflagellates, etc. 
expressed by more or less pronounced differences in appearance. This 
is a very loose statement and should certainly be qualified, anyone 
reading it for the first time might be led to believe that the sexual 
types of trypanosomes are well established. As far as we can gather, 
sexual differentiation among these parasites is purely arbitrary, and 
there is not the slightest proof to show that certain short forms with 
coarsely granular cytoplasm are female parasites, while the more slender 
trypanosomes with few granules are males. That these forms represent 
true sexual differentiation and that the parasites conjugate to produce 
zygotes has yet to be proved (see Dcflein, 1909). 
We think Woodcock wisely refers to the two ends of a trypano¬ 
some as the flagellate and non-flagellate, we however do not doubt that 
the flagellate end is the anterior; it certainly is in Herpetomonas and 
Crithidia. Two remarkable figures of T. lewisi from the blood of a 
recently infected rat are given; their posterior ends are drawn out to a 
great length tapering to a point. Woodcock states that in such forms 
the flagellum is very short; we must admit we have not seen this stage 
of T. lewisi. About the fifth to the ninth day after a rat is inoculated 
with this trypanosome, young developing parasites are usually found in 
large numbers in its peripheral blood, and we have frequently noted that 
they may be readily distorted in making a blood film, particularly if it 
is fixed by the wet method. 
In discussing the minute structure of trypanosomes Woodcock 
again appeals to Schaudinn’s work and reproduces his figures of 
the development of an indifferent trypanosome (T. noctuae) from a 
halteridium ookinete. Salvin-Moore and Breinl (1907) have recently 
questioned the correctness of Schaudinn’s interpretation of the appear¬ 
ances seen during the division of the nucleus of a trypanosome, claiming 
that the chromosomes are produced by the fixing and staining methods 
employed and that they are probably artefacts. If, as we believe, most 
of Schaudinn’s figures represent changes in the development of certain 
insect flagellates, we have no doubt that their nuclei contain definite 
chromatic bodies, but whether these are true chromosomes is at present in 
our opinion of little importance. 
Woodcock states there is no reason to doubt that the blepharo- 
plast of a trypanosome is not merely an extra-nuclear centrosome, but a 
true nucleus homologous with and equivalent to the principal nucleus, 
and that there are distinct centrosomes connected with both blepharo- 
plast and nucleus. The former he considers has an extra-nuclear 
centrosome at the base of the flagellum, and the latter an intra-nuclear 
