26 (90) Society for Experimental Biology and Medicine. 



In addition to the parasites mentioned, birds harbor very fre- 

 quently filaria and trypanosomes. In the case of the filaria, while 

 the peripheral blood may contain but a few, the heart blood may 

 contain large numbers. 



Trypanosomatic infection of birds is far more common than 

 has been supposed. The largest number of infected birds seen by 

 any one observer was eight, which were found by Dutton and 

 Todd in Senegambia. The reason why they have not been found 

 more commonly is because they are present in very small numbers, 

 usually not more than one or two flagellates in a drop of blood. 

 By microscopic and cultural methods the authors have been able 

 to detect trypanosomes in the blood of thirty -three birds. Of this 

 number, eighteen were detected by direct blood examination (of 

 the eighteen birds, ten were tested culturally and^gave growths) ; 

 and fifteen by means of their cultivation method — that is to say, in 

 fifteen cases where the microscope failed to show trypanosomes, 

 the culture method showed them to be present. This shows that, 

 as in the case of the bacteria, the cultural method is a more deli- 

 cate means of detection of small numbers of parasites than is the 

 microscope. 



The occurrence of these trypanosomes with reference to the 

 cytozoa mentioned is of special interest. Thus in thirteen of the 

 thirty-three cases, trypanosomes were unaccompanied by any intra- 

 cellular parasite, while in twenty they were associated with one or 

 more kinds of cytozoa. It was not an uncommon thing to find 

 multiple infections, that is, the same blood harboring, at one time, 

 in addition to trypanosomes, two or three different species of intra- 

 cellular parasites. Again, in addition to the fact that trypano- 

 somes may be present without another parasite, is the interesting 

 fact that when thus associated there is no constant relation between 

 the two. In other words, the same trypanosome may be found at 

 one time with a protcosoma, at another time with a lialteridium, or 

 with //. sacliarovi, or with H. majoris, etc. 



In twenty-five of the thirty-three cases mentioned, cultures 

 were obtained. Nearly all of these have been carried through a 

 series of subcultures or new generations. Here another important 

 fact was brought out. The cultural method is not only the best 

 means of detecting trypanosomes in the blood, but it is the best 



