IIo THE NORTHERN MICROSCOPIST. 

its capabilities Mr. Wenham’s new form, but by very different 
means. ‘The principle of the main limb moving in sector between 
vertical jaws has been already adopted by Swift and Son in a new 
form of student’s microscope, the model of which was an American 
invention by Wale; but the end aimed at in both cases was merely 
to control the centre of gravity in varying positions of the body, 
and the object was not fixed in any plane of motion of the optical 
tube. It has, therefore, been reserved for Mr. Wenham to intro- 
duce a form of stand which is said to possess perfect steadiness 
under high powers, is adapted for all the requirements of the most 
exacting “‘diatomist,” and is at the same time a serviceable instru- 
ment for general use. It is necessarily expensive. 


CESTOID WORMS. 
By Jno. B. WoLsTENHOLME, M.R.C.V.S. 
A Paper read before the Manchester Science Association, Feb. 14th, 1882. 
HERE are phenomena and histories, which we tacitly agree not 
to inquire into, and that to-be ignorant of is better than to be 
well versed therein. At a superficial glance one is almost tempted 
to say of cestoid or tape-worms that the less we have to do with 
them the better, and indeed I would endorse this readily if by so 
saying these creatures would stand on their dignity and decline 
any further acquaintance, but this they positively refuse to do, and 
seek every opportunity of becoming our guests and of being enter- 
tained at our expense. This sometimes becomes a most alarming 
item, for Dr. Krabbe, of Copenhagen, estimates that one-sixth (4) 
of the human mortality of Iceland with a population of 72,000, is 
caused by a single species of tape-worm in its larval condition; less 
serious, but still of great moment, is the record of disease and mor- 
tality caused by them in India, Australia, and indeed all over the 
world, varying only in degree. ‘This being true it is an imperative 
necessity that some should study and strive to know the details of 
their existence, if only with the object of adopting measures to 
minimise their baneful effects. Apart from this, I may add that to 
a student of nature the wonderful adaptations and co-ordination of 
means to secure their perpetuity render the investigation one of no 
small interest. | 
' ‘The generic name of ‘ Tzenia’ is derived from the Greek meaning 
“a band’ or ‘ribbon;’ whilst the term ‘cestode’ or ‘cestoid’ 
comes from the Latin ‘ cestus,’ signifying a ‘band’ or ‘ tie.’ 
_ These worms have been recognised for a very long period. 
