DETAILS OF FEEDING EXPERIMENTS. 493 



The examination of the third pig, which had heen fed three times, 

 took place 107 days after the first, seventy-one days after the second, 

 and forty days after the last feeding. Even while cutting through 

 the skin, I was convinced that the experiment had succeeded. The 

 hladder-worms were so abundant, that in many places the flesh seemed 

 changed into a honey-combed mass, somewhat like the spawn of frogs 

 or fish, and the number of the parasites amounted to at least 1 2,000. 

 The heart, lungs, and brain contained them, although in smaller 

 numbers than the locomotor organs. Instead of bladder-worms, the 

 liver exhibited only some tubercle-like nodules : the eyes were also 

 free from bladder- worms — that is to say, the ball of the eye — for 

 many were contained in the muscles of the orbit, and there were also 

 some under the conjunctiva. The largest bladders had a longitudinal 

 diameter of about 8 mm., while the smallest, which occurred in the 

 brain, measured only 2'5 mm. The other bladder-worms in the brain 

 were also smaller than those in the rest of the body, for the largest did 

 not exceed 4"5 mm. Most of them lay free on the surface of the hemi- 

 spheres, below the pia mater, or between the convolutions. Others 

 were sometimes free in the ventricles, between the convolutions, and 

 sometimes embedded in the substance of the brain, and then enclosed 

 in a sort of capsule. Some specimens were also found between the 

 lamellce of the dura mater ; these formed projections which had left 

 deep impressions on the internal surface of the roof of the skull. As 

 regards the stage of development of the head, the parasites might be 

 divided into three groups, which probably corresponded with the three 

 feedings. The largest were fully developed, others exhibited various 

 earlier stages of the hooks and suckers, while the youngest had only 

 the first rudiments of a head. The latter were found exclusively in 

 the cavity of the skull, from which, however, the representatives of 

 the second stage seemed to be absent. 



The fourth pig, which was killed eighty-two and twenty-nine days 

 after the first and second feedings respectively, appeared at first quite 

 healthy. Only after a long search was a single bladder-worm found 

 deeply buried in the muscles of the neck. It was the size of a large 

 pea, and was fully developed. 



In the case of the fifth pig, as in the first and second, excisions of 

 muscles were made from time to time, in order to study the gradual 

 development of the bladder-worms, which were again present in con- 

 siderable numbers. Eight days after the feeding, no parasites could 

 be found, but many were visible on the second and third excisions, 

 which were postponed till the thirtieth and ninety-fifth days. The 

 pig, which had meanwhile been subjected to other experiments, lived 



for some time, and on dissection (six months after the feeding) it ex- 

 Digitized by Microsoft® 



