468 CYSTIC STAGE OF T.ENIA SAGIXATA. 



The very reverse of this experiment is furnished by Zenker's case, l 

 in which a calf was fed with only a single proglottis whether full of 

 eggs or not is doubtful and remained in perfect health, yielding only 

 three bladder-worms in the muscles of the back. 



To our knowledge of the structure and development of this blad- 

 der-worm all these observations have added but little. As far as 

 anatomical facts are concerned, they simply corroborate my former 

 statements. Only one point has been made clearer, and that by Ed. 

 van Beneden, who, as was formerly remarked (p. 360), was fortunate 

 enough 2 to observe numerous young Cysticerci still retaining their 

 embryonic hooks twenty-one days after feeding. In three cases he 

 was able to find all the six hooks, while in other cases only one or a 

 few were to be seen. A sketch he was kind enough to send me shows 

 the six hooks at some distance from one another, but yet still approxi- 

 mated in pairs, and at their original place of insertion by the side of 

 the rudimentary head, which had reached the stage shown in Fig. 

 264. In form, size, and histological structure, the young bladder- 

 worms had the greatest resemblance to the worms first observed by 

 me. Calcareous corpuscles and vessels were still absent. The heads 

 in many specimens were still indistinct, or in process of development. 

 Their place of formation did not appear quite constant, seeming some- 

 times to lie somewhat laterally instead of in the longitudinal axis of 

 the bladder. 



We have, however, to thank the above investigators for important 

 results as to the pathological influence of these parasites. The 

 memoirs of Hosier, 3 Ziirn, 4 Simonds and Cobbold, and van Beneden, 

 are specially worthy of mention, because they have elucidated many 

 points with respect to the nature of acute cestode tuberculosis. 



Zlirn's case has been perhaps most accurately followed in its 

 pathological bearings. A calf three months old, which had been fed 

 with fifty-seven ripe proglottides, exhibited symptoms of disease on 

 the fourth day after infection. The animal had a high temperature 

 (40 C., instead of 39'2) and a somewhat raised pulse, ate little, and 

 had an inflated belly, which was sensitive to touch. These symptoms 

 were probably caused by the wandering of the embryos, as is shown 

 by the fact that they disappeared after a short time, with the excep- 

 tion of pain which seemed to be felt when the walls of the belly 

 were pressed. A slight fever (with a temperature of 40'3) also per- 



1 Sitzungsb. d. phys. med. Gescllsch. Erlanyen, Heft iv., pp. 71, 87, 1872. 



2 The investigations referred to were communicated to me in manuscript by my esteemed 

 friend, and have since been published, Bull. Acad. Sci. Belyique, t. xlix., p. 659, 1880. 



3 " Helminthologische Studien und Beobachtungen," pp.1-22 : Berlin, 1864. 



* "Arbeiten der landwirthschaftl. Versuchsstation Jena," Zeitschr. f. Parasitcn- 

 kunde, Bd. i., p. 363, 1869. 



