DISEASED PORK, AND MICROSCOPIC WORMS IN MAN. 145 
to be inclosed witbin a circumscribed space of a less elongated 
and more regular elliptical form than the external cyst, as if 
witbin a smaller cyst contained in tbe larger, like the yolk of 
an egg surrounded by its albumen and shell. The worm does 
not occupy more than a third part of the inner space. A few 
of these cysts have been seen to contain two distinct worms ; 
and Dr. A. Farre, who has paid much attention to the subject, 
has shown me a drawing which he made of one of the cysts 
containing three distinct worms, all of nearly equal size. 
“ The cysts vary in form as well as size, being more or less 
elongated, and the opaque extremities being further extended 
in some than in others ; in a few instances only one of the 
extremities is thus produced. Occasionally the tip of one of 
the extremities is observed to be dilated and transparent, as 
though a portion of the larger cyst were about to be separated 
by a process of gemmation/-’ 
The coiled parasite is seen in its cyst in the centre figure of 
the annexed plate, and the peculiarities of the worm are well 
brought out from the imbibition of an ammoniacal solution of 
carmine — a method of preparation which often enables us to 
trace the characters of microscopic objects which are otherwise 
ill-defined.* The body of the parasite is seen clothed with a 
transparent skin, which does not imbibe the carmine so readily 
as the softer structures within. The thickness of the skin has 
been estimated by Leuckart at O'OOl millimeters. Attention 
has been drawn by Henle, Luschka, Kiichenmeister, and 
others, to the wrinkled appearance of this skin, which in all 
perfect specimens is smooth, and not convoluted. Leuckart 
says that when the parasite is injured, rings round the body 
are commonly visible. The skin is structureless. Beneath 
the skin is a layer of a fine granular matter with the appear- 
ance of longitudinal stripes and numerous bright refrangent 
corpuscles. This has been looked upon as the muscular 
structure of the trichina. 
From the cutaneous muscular structure there are two bands, 
or water tubes, stretched from before backwards on the lateral 
parts of the body. These are pale, but with well-defined outlines, 
and stretched alongside of them are small round or oblong 
yellow corpuscles. 
The alimentary canal extends through the whole body from 
the narrow end or head to the broad anal extremity. The 
organs of generation do not exist in the encysted worms, and 
only when they attain their full development in the alimentary 
* The specimens from which the two figures of the parasite have "been 
drawn were prepared by Dr. T. R. Fraser, so well known now for his 
interesting discoveries concerning the action of the Ordeal Bean of 
Calabar. 
