148 
E. A. MINCH IN AND H. M. WOODCOCK. 
the case both as regards the habitat of the trypanosomes and 
tlieir behaviour in the bird at different seasons,, and also in 
regard to the chief morphological types found. 
In the winter and spring months the bone-marrow is the 
chief seat of the parasites ; indeed, for all that we could learn 
to the contrary, they may be restricted to this situation. The 
blood of owls 8, 13 and 14 was examined living on many 
occasions, both in the day-time and at night, and numerous 
stained preparations of the peripheral blood and the internal 
organs (lungs, spleen, etc.) have been searched, without in 
any case coming upon a trypanosome. 
Nevertheless, from the experiences of one of us in reference 
to this point, in working on other birds, we should not like 
to say certainly that the parasites do not occur at all in the 
general circulation at this period. 1 Most unfortunately the 
indispensable test, that, namely, of taking cultures from the 
blood, was quite a failure in its application in this case. 
Several culture-tubes were inoculated from the peripheral 
blood of the above owls, which remained uncontaminated, or 
practically so, by bacteria, but they were also sterile as 
regards trypanosomes. The disappointment was, however, 
that in tubes inoculated from the bone-marrow of these birds, 
in which trypanosomes were kuown to be present, no cultural 
forms developed. In no instance, in fact, did we succeed in 
obtaining a culture of the owl-trypanosomes, a very different 
result from the usual experiences with the culture-method. 
-A s Rosenbuscli ( 15 ) has obtained cultures of the parasites — 
i.e., as will be shown later, of the trypanosomes — of the 
little owl, we can only surmise that the fault in our case lay 
with the tubes used. 2 
1 Mayer, however, has noted (12) the occurrence of the parasites (in 
the large, massive form, c.f. below) in the general circulation in the 
early part of the year (January) in the case of the trypanosome of 
Syrnium aluco. 
-We had no facilities for making culture-tubes at Rovigno, and had 
to rely upon some taken with us ; many of them were rather old by the 
time they were required ; others had to be boiled up and fresh salt- 
