38 THE NORTHERN MICROSCOPIST. 

that each had its favourite host, and that it seemed to be a pretty constant law 
that both were seldom or never found to exist in the same animal. 
The Cysticercus cellulose was the higher larval intermediate stage of growth 
of the Zenza solium, one of the tape-worms infesting the human body, and in 
this its encysted conditions was technically called a scolex, a name given when 
it was ignorantly supposed to be a distinct animal. Cystécercus cellulose was 
then described; its four projecting discs or suckers, conical rostellum, double 
circle of hooklets, calcareous particles, and water vascular system of vessels, 
being illustrated by slides and diagrams. Attention was drawn to the curious 
fact that Cysticercus in swine was alone distinguished from that of man by 
possessing only twenty-four to twenty-six hooklets, instead of thirty-four to 
thirty-six as occurs in the human subject. The body of a Cysticercus was 
entirely asexual, and terminated posteriorly in a bladder or cyst in which the 
animal was often found invaginated like the inverted finger of a glove. 
Although a misnomer, it was convenient to speak of the anterior extremity of a 
Cysticercus as the head, but there were no traces to be found of oral appendages 
or digestive organs, the animal appearing to be nourished by imbibition through 
the skin. Unlike its mature relation, Tzenia, a Cysticercus was never found 
in any part of the body communicating with the external air, but nearly always 
encysted and inhabited the voluntary muscles, inter-muscular areolar tissue, liver, 
heart, lips, tongue, and other parts of the body, including the eye and brain. 
In open cavities it floated without any enveloping cyst. The cyst was developed 
at the expense of the tissue in which the animal was imbedded. It was com- 
monly found in swine, less commonly in the ape, dog, and sheep, and, fortuna- 
tely for us, very rarely in the human subject. 
The life history of Cysticercus cellulose was then described. The mature 
joints or of Zenza solium being expelled from the body of the animal harbouring 
them were conveyed with excrementitious matter on to the land, or found their 
way into wells, ponds, or streams situated near human habitations. The ova 
being protected by an exceedingly tough chitinous shell retained their vitality 
for a great length of time, and, becoming attached to vegetable matter, were 
swallowed by different animals, such as pigs and sheep, eventually developing 
into Cysticercus in their bodies. In cases which had occurred in the human 
subject salads and other uncooked vegetables, also fallen fruit were the means 
of infection. |The disposal of sewage on market gardens and farm lands was 
for this and other reasons not such an unmixed blessing as some people supposed. 
The ova being swallowed the contained embryo or pro-scolex (vesicular in form 
and only about 1-1250 of an inch in diameter), was set free either during mas- 
tication or digestion and resisting the action of the gastric secretion immediately 
commenced to migrate, passing through the intestinal wall by means of six 
boring spines which being approximated formed an exceedingly minute piercing 
instrument. Gaining access into an intestinal vein it was carried by the portal 
vein to the liver, or by a current of arterial blood was transported to distant 
parts of the body, and becoming encysted attained its intermediate stage of 
development as a Cysticercus. 
The transition of the scolex into the Tzenia was then described. The measle 
being swallowed, the vesicle or bladder disappeared, the cysticercus however 
resisting the action of digestive secretions retained its vitality, joints or strobila 
were developed by a process of budding and passing on to make room for those 
more recently formed, became eventually sexually mature, each joint being her- 
maphrodite and largely composed of reproductive organs. It has been com- 
puted that each sexually mature joint contained 30,000 ova, and the wonder 
was that measled meat was not more commonly found, but the majority of the 
eggs eventually decomposed and perished, or were consumed by animals whose 
organism was unfavourable to their development. The use of the suckers and 
hooklets was now apparent, the so-called head of Zenza solium being so firmly 
fixed to the intestinal wall that it was only rarely it could be found. The upper 

