128 Tue MICROSCOPE. 
cept, of course, the Pope, and it is scarcely surprising that the 
latest English writer on the Infusoria should occasionally repeat 
some of Carter’s or Leidy’s assertions with an air of doubt. If 
Kent has been unable to verify Carter’s statements, it is his 
duty to say so, and when any other worker in the same depart- 
ment is able to add even a single fact confirmatory of either 
observation it is no less his duty to be not “ backward in coming 
forward.” 
The formation of the contractile vesicle in an Infusorian 
ordinarly invisible, and the presence or absence of a brush-like 
tuft of cilia at the posterior extremity of the small little crea- 
ture, may seem like anatomical niceties hardly worthy of atten- 
tion, but every fact is important, and every addition to the sum 
of human knowledge though it may be infinitesimal, will add 
somewhat to the sum of human happiness either here or here- 
after. 
In reference to the pulsating vacuoles of the common Par- 
amecium aurelia, mull., Kent states that the stellate contour at 
diastole is probably the result of abnormal pressure. The effect 
can be produced by any one by the use of a thin cover without 
a supporting cell. In a situation where the animalcule’s move- 
ments are much restricted by the pressure, the two contractile 
vesicles, even previous to systole, have developed about their 
margin often as many as eight lateral, pyriform vacuoles which, 
at the moment of contraction are left to coalesce and so pro- 
duce, in part, the ordinary, spherical vesicle. Kent adds, appa- 
rently with doubt, that ‘“‘according to Carter” these pear- 
shaped vacuoles are prolonged as thread like channels through 
the substance of the infusorian. 
Having recently examined numerous specimens of Para- 
mcium from a distant locality, I have been able to corroborate 
Carter’s statement. ‘The appearance is an interesting one. 
From almost every pear-shaped vesicle the small or stem end 
is elongated as a fine but conspicuous channel which is finally 
lost in the parenchyma. Some of these filiform canals are occa- 
sionally persistent, but when the accessory vacuoles are visible, 
they can be followed up, down, through and around the endo- | 
plasm in a beautiful star-like pattern. A minute, spherical ves- 
icle first reappears centrally after cystole, which, gradually en- 
