100 OBSERVATIONS ON THE STRUCTURE OF THE RETINA. 
pears to be drawn inwards, forming a hollow; at the bottom 
of which, the granular material is deposited from which the 
suckers, booklets, and calcareous granules are formed, as 
above described. — Royal Society . 
ON THE PRODUCTION OE TiENIA CONSIDERED IN 
RELATION TO PUBLIC HYGIENE. 
By Dr. Riecke. 
It has been well proved by the experiments of Kiichen- 
meister, that individuals fed on pork tainted with es measles,” 
and containing the peculiar entozoon called Cysticercus cel - 
lulosce , become subject to tape-worm. Various German 
writers have supposed that these entozoa are destroyed by 
boiling, salting, and smoking the pork ; and Dr. Riecke, of 
Nordhausen, has published a paper, in which he recommends 
the prohibition of the sale of pork, unless it has previously 
undergone these processes. In support of his views, he 
states that taenia is an exceedingly frequent complaint in the 
neighbourhood of Nordhausen, where there is a large con- 
sumption of raw pork by the people ; and, on the other hand, 
that in Altmark, where this practice is not prevalent, he has 
only seen six cases of the disease among about 10,000 patients 
who have been under his care, during a period of fourteen 
years. He therefore considers that, in order to prevent the 
spread of this parasite, all pork should be prepared, by 
salting and smoking, before it is sold, or permitted to be 
used by the people. — Henke's ZeitschrifL — Edinburgh Medical 
Journal . 
OBSERVATIONS ON THE STRUCTURE OE THE RETINA 
IN CERTAIN ANIMALS. 
By H. Muller. 
I have show in my work upon the e Retina, 5 that this part 
furnishes microscopic characters which may be employed in 
the systematic distribution of vertebrated animals, to such an 
extent, that it is often possible to determine the class, the 
order, and even the genus of an animal from a small fragment 
of its retina. 
