A. Porter 
241 
Laveran and Lucet state that the host cell of L. smithi, parasitic in the 
turkey, may be either oval or greatly elongated. As stated above, I 
have seen Leacocytozoa living in the common fowl in England, a para¬ 
site probably the same as that of Mathis and Leger, and it does not 
produce spindle elongation of the host cell. The property of producing 
marked deformation of the host cell, then, breaks down as a character of 
avian Leucocytozoa. 
Again the fourth character given is that male, female and young 
parasites, possibly immature gametocytes, are found in the circulating 
blood. I would suggest that there is another possibility—that some of 
these forms are not gametocytes but are schizonts. This possibility has 
been overlooked. 
With regard to the seventh character Mr Wenyon states that the 
parasites never leave the host cell to move about in the blood plasma. 
Because Mr Wenyon has not seen this phenomenon, it does not follow 
that it does not occur. Further, I would ask how the primary infection 
of the host cell takes place and how the periodicity exhibited by L. caul- 
leryi described by Mathis and Leger is to be explained, were there not 
free forms in the blood at some staafe. 
o 
A still more astonishing character (!) is given when it is stated that 
the “asexual mode of reproduction is unknown.” It is surprising that 
lack of knowledge of various phases of the life history of any organism 
should be quotedas evidence regarding the character of that organism. 
Apart from that, the statement is inaccurate, for schizogony of Leuco- 
cytozoon lovati of the grouse is now known. (See Abstracts Proc. Zool. 
Soc. (1910) No. 84.) 
Had Mr Wenyon taken note of the sections of my article dealing 
with the general description, movements, comparative morphology, 
multiplication and reproduction, he would have acknowledged that 
most of his “characters,” and particularly those of the leucocytic para¬ 
sites of mammals, were clearly set forth therein, but without the 
dogmatic assertion or suggestion that they were invariable features or 
characters of the organisms. When Mr Wenyon can refer us all to a 
generally accepted complete life cycle of an avian Leucocytozoon as well 
as to an equally generally accepted complete life cycle of a mammalian 
Leucocytogregarine, then it will be time to draw up tables of differ¬ 
ences between the various parasites under discussion. Meanwhile such 
character differences as those used by Mr Wenyon are very artificial, 
and as shown, often quite inaccurate. 
A side issue is raised when the question of Leishmania and Herpeto- 
monas is discussed by my critic. But though irrelevant to Leucocytozoa 
