598 DEVELOPMENT OF THE ECHINOCOCCUS-BLADDE?. 



size and appearance (sometimes measuring as much as 0'028 mm.). 

 Most of these were pale and delicately outlined, and to some extent 

 like drops, but there were others which were remarkable for the 

 granular nature of their contents, and there were even granular 

 cells of considerable size, not unlike pus corpuscles. In the larger 

 Echinococci the latter sometimes exhibited stellate ramifications and 

 a clear nucleus which shone through the granular substance. In 

 these large Echinococci (there were some specimens of from 2 to 25 

 mm.) it was seen that the different kinds of cells exhibited a definite 

 arrangement. Most externally lay the small cells, and further inwards 

 the large drop-like bladders, while the granular cells were distributed 

 at irregular intervals over the surface. 



I have not as yet succeeded in the attempt to observe the young 

 Echinococci in their earliest condition. A pig which was fed twice, at 

 intervals of five weeks, with a large number of ripe Tcenice, and was 

 killed fourteen days after the last feeding, only exhibited worms similar 

 to those which originated from the first feeding.^ Some of them 

 measured as much as 3 mm., tlie others varied from 1 mm. upwards, 

 and even with the naked eye the above-described granular and radiate 

 cells could be seen shining through. What was both new and striking 

 to me was a thick border of granular spindle-cells, situated upon the 

 now distinctly laminated cuticle, from which they could only with 

 difficulty be separated. They agreed, however, with the adjoining 

 granular cells, except in the difference of their form. 



Besides the structures just described, the liver of the animal con- 

 tained under the serous coating a number of small round or oval 

 cysts (of 0'3 to O'S mm.). These I at first also regarded as EcMiwcocci, 

 especially since, like the latter, they belonged to the interlobular tissue, 

 but I discovered to my surprise that instead of a parasite they en- 

 closed a vegetable hair. This must have originated from the stomach, 

 whose walls it had perforated, and afterwards penetrated into the hver. 

 Apart from the analogy of this structure with the caterpillar-hairs 

 found encapsuled in the mesentery and liver of the frog, this view 

 was rendered more probable by the fact that the cysts were situated 

 almost without exception on the concave surface of the liver. The 

 comparison of these structures with the Echinococcus-cjsts was of 

 interest, since not only were both bounded externally in the same 

 manner by a layer of connective tissue, but enclosed the very same 

 enveloping mass of granular cells. 



^ In the same organs as the above-described young bladders, Naunyn repeatedly found 

 forms which perhaps represented the first stage of the bladder-Worm. They were small 

 round structures about four times the size of an embryo, and were composed of granular 

 globules, and surrounded by a simple hyaline membrane. No embryonic hooks could be 



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