STUDIES ON AVIAN H^MOPROTOZOA. 649 



instances where anything unusual is to be noticed are in old, 

 used-up tubes, in which the liquid is full of clumps of agglo- 

 merated parasites, and many are degenerating and dying. 

 These masses tend to settle to the bottom of the liquid, and 

 may be apparent as a small quantity of whitish-yellow scum. 



Inoculation of Birds with T ry p an o somes. — I en- 

 deavoured to produce an infection with trypanosomes in birds 

 which I had found to be uninfected. So far, the oidy means 

 at my disposal of doing this has been by inoculating; and 

 most, certainly, of my attempts in this direction failed. In 

 all about twenty-five inoculations were performed, and only 

 in three cases was any positive result afterwards observed, 

 which might be due to the inoculation. Many of the failures 

 resulted from attempts to inoculate other (uninfected) 

 birds with the trypanosome of the chaffinch and redpoll. 

 Thus, a couple of linnets, one of them inoculated twice, 

 proved negative. Also a barn-owl was tried with no more 

 success. I was rather surprised, however, to find that a 

 canary, which I thought would be very likely to prove 

 susceptible, refused to become infected. It was inoculated 

 three times, twice from cultures, and once from fresh 

 (infective) blood, mixed with a little salt-citrate solution. 



A few words in connection with the modus operandi. 

 To begin with, I inoculated the birds intra-pleurally, as 

 recommended by Novy and McNeal, but 1 lost two or three 

 redpolls straightway as a result of the operation. It was 

 very cold weather at the time, and this may have conduced to 

 their collapse. Since then, I have always found it much 

 more satisfactory to do the birds intra-peritoneally or intra- 

 muscularly (in the pectoral muscles). None of the birds so 

 inoculated suffered any ill-effects, even though, occasionally, 

 they were done in both ways at once. The "dose" was 

 generally four or five drops (from one eighth to one sixth of 

 a cubic centimetre) of the liquid in the tube. This contained, 

 of course, numbers of parasites. 



With regard to the three cases in which the trypanosomes 

 were observed subsequently, I may point out that I had made 



