ETIOLOGY 275 



and lumbar nerves bacteria, especially streptococci and less 

 constantly bacilli, to which he attributed the cause. More re- 

 cently Schneider and Buffard have apparently demonstrated that 

 a protozoon, one of the Trypanosomae , is the specific pathogenic 



agent. 



The Trypanosoma varies greatly in form at different stages 

 of its growth. In the exudate of the ear tumefaction, without 

 as yet other symptoms, it is found as minute granules in groups 

 or larger spherical bodies resembling very large micrococci, 

 each having a nucleus. There are larger bodies in which a 

 delicate membranous covering encloses one, two or three masses 

 of chromatin which extend to form one or more points (club 

 shaped or fusiform). Each chromatin mass has a nucleolus 

 on its outer surface or slightly apart from it. Twenty-four 

 hours later there may be added, (i) short, thick chromatin 

 bodies with two slightly undulating, pointed, membranous pro- 

 longations ; (2) more delicate, fusiform bodies, each with one 

 chromatin nucleus, a detached nucleolus, and the membrane 

 prolonged into two actively moving flagella ; (3) larger pyri- 

 form bodies with chromatin nuclei and nucleoli and the mem- 

 brane prolonged into one or several flagella ; (4) fusiform 

 hodies thick or delicate, each having a chromatin nucleus and 

 nucleolus, and arranged singly or in groups of two, four, six 

 or more united together at one end and diverging at the other. 

 These last are 20 to 30yu long by 1.5 to 2// broad and perhaps 

 may be the adult form of the parasite from which the small 

 granular or spore forms found in the most recent lesions are 

 derived. The fusiform outline, the deep staining central mass 

 with its adjacent nucleolus, and the pointed or flagellated mem- 

 branous prolongations, more or less motile or undulating are 

 characteristic features. 



In its morphology and evolutionary forms the trypanosoma 

 of dourine has not been shown to differ from that of surra. 

 The granule form, the spherical, the club shaped or pyriform 

 bodies, the fusiform with more or less stellate groupings seem 

 to be generic characteristics. The specific distinction is found 

 in the pathogenesis as shown by the two diseases (surra and 

 dourine). 



