do4 Prof. R. Leuckart on the Developmental 
closes an oil-drop and may readily be mistaken for an egg or 
yelk-mass. 
Encapsulation in the interior of the first host is consequently 
in this case an accidental phenomenon, and by no means the in- 
troduction to a further metamorphosis as in the Trichine. This 
belongs, in the present parasite, rather to the embryos only which 
emigrate through the intestine and bronchi. 
As I could not manage to keep these embryos alive for any 
length of time in water or moist earth, even with addition of ex- 
crement or bronchial mucus, I administered them, with bread, to 
a mouse. I hoped to be able in this way to cause the further de- 
velopment of the young worms; and in this | was not deceived. 
On examining my experimental animal six weeks after the com- 
mencement of the experiment, I found, in the very first fragment 
of muscle which I placed under the microscope, a round worm 
rolled up in the manner of Trichina, enclosed in a capsule about 
0:3 millim. in diameter, which proved on closer examination to 
be a second developmental form of my worm. Then wherever 
I sought for them in the muscles of the trunk I found the same 
worms, but most abundantly in the regions of the neck and 
breast ; a few also occurred in the heart and cesophagus and even 
in the loose connective tissue permeated by fat between the 
organs of the neck, although elsewhere they might be looked for 
in vain except in the striped muscles. The total number of 
the parasites in the body of my experimental animal must have 
been many hundreds. 
On a superficial examination the capsules resembled those of 
Trichine, but they were all round or only a little elongated. 
When they were closely examined, however, many other differences 
were detected. In place of the structure so characteristic of the 
Trichine, the wall of the cyst here presented nothing but a closely 
interlaced, firm and tough connective tissue, which was sur- 
rounded by growing nuclear structures, and enclosed innumer- 
able granular cells (0°025 millim.), which were constantly pushed 
to and fro by the movements of the convolute worm. At the 
poles of the cyst a yellowish pigment was deposited in the 
nucleate tissue which was here particularly accumulated ; and 
this pigment sometimes extended over the whole capsule. Here 
and there single fat-masses were also seen at this point. 
Except im its dimensions (length 0°8, breadth 0:04 millim.) 
the enclosed worm showed an unmistakeable similarity to the 
embryos above described. This applies especially to the form of 
the body and the structure of the intestinal canalf; only the 
pharynx has already a muscular texture (even to the posterior ex- 
tremity), and the intestine is of a brownish colour. The walls 
of the body are of considerable thickness, and contain numerous 
