84 
BRITISH ASSOCIATION.— 1835 . 
the little animal dies, and in the dead state comes to act as a foreign 
body on the cyst which contained it;—That the cyst, thus irritated, 
falls into a state of inflammation, the effects of which are traceable 
through a variety of stages, to the almost total disappearance of both 
cyst and hydatid. The cyst first becomes thickened; lymph is 
thrown out on its internal surface, giving it a roughened granular 
appearance. The hydatid becomes opake, and its fluid contents 
muddy. An adhesion, probably of a glutinous or mechanical nature, 
is established between the lymph and the exterior surface of the hy¬ 
datid. The fluid of the hydatid is then absorbed, and its empty 
bag squeezed up in the centre of the solidified tumour. At a period 
somewhat later all traces of the hydatid disappear, and the remaining 
mass consists of nothing but the altered cyst, filled with lymph and 
some curdy matter. The tumour diminishes in bulk, it becomes of 
a cheesy consistence, and finally is converted into a small solid 
nucleus of earthy matter, devoid, as it would appear, of any irritating 
properties. 
Dr. Houston differs from other writers in referring the whole of 
the morbid changes to the cyst, and not to the contained hydatid, 
which he says is absorbed in the progress of the phsenomena conse¬ 
quent upon its death. He does not concur with those who are of 
opinion that malignant and tubercular diseases are of the nature of 
parasitical animals. No facts have hitherto been advanced sufficient 
to establish the position that any such diseases are, either at their 
commencement or at any subsequent period of their progress, of 
such a character. No animal has ever been seen of any definite 
shape in connexion with them; and where the powers of the mi¬ 
croscope can be brought with such effect in aid of investigations of 
this nature, why, it may be asked, if such pestiferous animals exist, 
have they not ere this been demonstrated ? The fact is, that all the 
circumstances connected with the growth and decay of such para¬ 
sites as our senses can take cognisance of tend to a conclusion of an 
opposite nature, viz. that these animals have their periods of ex¬ 
istence as living beings, and having passed from this state, instead 
of polluting the whole frame, or running into extensive diseases, dis¬ 
appear, and leave little or no injurious effects behind them, unless 
what may have arisen from their mechanical interference with the 
functions of some vital organ. 
The author exhibited numerous preparations and drawings illus¬ 
trative of the facts advanced in the paper. 
On the Entozoa which are occasionally found in the Muscles of the 
Human Subject. By Professor Harrison. 
The Professor exhibited preparations and drawings of a speckled 
appearance not unfrequently met with in different parts of the mus¬ 
cular system, and detailed the particulars of several cases in which 
it had existed: he expressed his full concurrence with the opinions 
advanced by Mr. Owen, in the Transactions of the Zoological Society 
