TRYPANOSOMES OF BIRDS 577 



be carried in other ways has been proved to occur. Thus, Schuberg and 

 Kuhn (1911) obtained a mechanical transmission by means of Stomoxys 

 calcitrans, and Sergent, Ed. and Et. (1906a), with a tabanid fly, Tabanus 

 nemoralis. 



III. TRYPANOSOMES OF BIRDS. 



The trypanosomes of birds are considered here amongst the forms 

 which develop in the anterior station in the invertebrate, though actually 

 in no case is the vector known, much less the type of development which 

 occurs. Mosquitoes have been suspected of being the transmitting hosts, 

 and certain observers have noted flagellates in the salivary glands of these 

 insects, but there is no evidence that these have been derived from bird 

 trypanosomes. It is quite possible, when the true intermediate host is 

 discovered, it will be found that development of the trypanosome takes 

 place in the posterior station. 



The first satisfactory account of the occurrence of trypanosomes in 

 birds was that of Danilewsky (1888). Since then a large number of 

 forms has been described from well over a hundred species. In the great 

 majority of cases, little more has been done than to give an account of the 

 trypanosomes as they appeared in a single blood-film; no detailed study 

 has been carried out. In one or two instances, however, more extended 

 observations have been made. Schaudinn (1904) published a remarkable 

 account of the development of the trypanosome {T. noctuce) of the little 

 owl. He stated that an alternation of a trypanosome with an intra- 

 cellular halteridium phase occurred in the life-cycle. Subsequent observa- 

 tions, in spite of various attempts by Woodcock (1909) and others to 

 substantiate Schaudinn's views, have clearly demonstrated the fallacies 

 of his conclusions. 



Trypanosoma paddae Laveran and Mesnil, 1904. — The best account of 

 a bird trypanosome is that of Thiroux (1905), who described the infection 

 due to T. paddce Laveran and Mesnil, 1904, in the Java sparrow {Munia 

 oryzivora). The trypanosome was first seen by Levaditi in birds imported 

 to France. By means of this strain, Thiroux was able to infect other birds 

 and to study the course of the infection. Inoculated intraperitoneally, 

 trypanosomes appeared in the blood of the birds in twelve hours, whereas by 

 the intramuscular or subcutaneous method the incubation periods were nine 

 and twelve days respectively. Furthermore, there was marked irregularity 

 in the results of inoculation. Some birds only became infected after a 

 second inoculation. After their appearance in the blood, the trypanosomes 

 increased in number during nine to fifteen days, after which the number 

 declined day by day till they could only be found with difficulty. In some 

 cases the infection brought about the death of the birds. The trypano- 

 I. 37 



