388 



Mr. C. H. Martin and Miss M. Robertson. [June 18, 



that if one regards the events in the course of absorption by which the 

 liquid contents of the cseca and intestine are converted into the practically 

 solid fseces, it becomes difficult to believe that this solution can at best 

 represent more than one out of a series of many stages. 



The Flagellate Parasites. 



The flagellate parasites found in the caecum, as has been stated above, can 

 be divided into four groups, A, B, C, D, of which we only need here 

 particularly to consider A, B, and C. D is a sharply marked type, found in 

 small numbers on two occasions, with an anterior and a posterior trailing 

 nagellum, which can be coiled round the body. It is of very small size, 

 roughly half the size of the smallest A form seen, and of approximately 

 torpedo shape. 



The chief difficulty in dealing with the remaining three groups, A, B, C, 

 is that although large numbers of individuals can be found in which the 

 characters of each group are sharply marked, yet numerous transitional 

 forms are to be seem. Under these circumstances we do not feel inclined, 

 until we have obtained a great deal more evidence from artificially infected 

 chicks raised in an incubator, to decide definitely between the two alterna- 

 tives of considering A, B, C as various forms of a mixed infection or as 

 stages of a single life cycle. The small amount of evidence we have at 

 present points clearly to a transition from A to B, and we have observed 

 some cases of which the most natural explanation would be to regard 

 A, B, C as stages in one life cycle. 



A. Trypanosoma eberthi, Kent. Plate S, fig. 1. — This is the form which 

 we are inclined to believe Eberth had before him when he wrote his 

 description of Trypanosoma eberthi. It is characterised by a rather elongated 

 body, a very well marked undulating membrane, along the edge of which a 

 flagelluni runs from the anterior end of the animal to end freely at the 

 posterior end. The living animal, when seen on a cold stage in salt solution, 

 is easily picked up by the rippling movement of the undulating membrane. 

 In the living animal the nucleus can be readily seen as a rather cone-shaped 

 light area containing some small granules lying in the anterior region of the 

 animal. Along the base of the membrane a well marked line can be seen, 

 and in its neighbourhood there is always one and sometimes two rows of 

 blocks. In a suitably placed animal an axostyle, apparently resembling that 

 described in Trichomonas, can be seen. In preparations stained with 

 haemalaun and eosin, the nucleus is readily recognisable, and a fairly large 

 round body is seen at the anterior end at the origin of the flagellum ; it is 



