280 PARASITES OF MAN 



disease. The sacs in this case were remarkably small ; never- 

 theless their corpuscular contents indicated their true nature. 

 The pseudo-navicellae measured only ~ 5 " in diameter. Amongst 

 other contributions of interest I may refer to those of Dufour, 

 J. Miiller, Creplin, Kolliker, Keferstein, Stein, Drummond, 

 Lieberkiihn, and E. Ray Lankester. I doubt if the vegetable 

 organisms described by Prof. W. T. Gairdner can be refmvd 

 to this group of parasites. At all events, by whatever name 

 these spurious entozoa are called, they were first discovered by 

 Dufour in insects, by Miiller in fishes, by Miescher in the mouse, 

 by Dujardin in the mole, by Hessling in the larger quadrupeds, 

 and by Gubler in man. The results of my own examinations 

 may be briefly re-stated. In the flesh of cattle I found 

 psorospermial sacs varying from ~" to ' in length, and in 

 that of sheep from jj/ 7 to -^' '. The bodies were enclosed in 

 well-defined transparent envelopes, and their contents exhibited 

 indications of segmentation. In some specimens the segments 

 displayed themselves as a complete cell-formation, the contents 

 of each cell being uniformly granular. Under the J" objective 

 the contained granules were clearly visible, and on rupturing 

 the sac their peculiar characters were at once manifest, each 

 granule or corpuscle represented a pseudo-navicel, all displaying 

 a tolerably uniform size, averaging ^' in diameter. Some of 

 the corpuscles were round, others oval, several bluntly pointed 

 at one end, many curved and fusiform, not a few being almost 

 reniform. Highly refracting points or nucleoli were visible in 

 their anterior. 



Turning to the practical aspect of the subject, I remarked 

 that these bodies had nothing to do with the cattle plague. No 

 one who carefully examined the flesh of animals that had died 

 of rinderpest had failed to discover them ; yet, in one or two 

 instances they appear to have escaped notice. When it is con- 

 sidered how long it takes us to examine a few grains weight of 

 muscle carefully, it is obvious that the body of a large beast 

 might contain many hundreds of these organisms without our 

 being able to detect their presence, except by a prolonged 

 investigation. In the few rinderpest beasts, portions of whose 

 flesh I submitted to the microscope, I should say there were 

 not more than 100 of these bodies in one ounce of meat ; but in 

 the heart of a healthy sheep (which I afterwards ate) I calcu- 

 lated there were about 1000 parasites to the ounce, and in the 

 heart of a healthy bullock (which likewise served me for a 



