1900-1.] Dr J. Y. Simpson on Binary Fission of Ciliata. 419 
seems more evident ( Protozoa , Bd. I. Heft III. p. 1592), he is 
simply entering a protest against Maupas’ action in limiting the 
process of degeneration to one special late period in the infusorian’s 
life — thus in the case of Stylonicliia pustulata it is not reached 
until from the 170th to the 200th generation — he is surely to he 
commended. If there is degeneration at all, it is most improbable, 
on all other analogy, that it should set in at a certain fairly 
definite point — so late as the last third of the creature’s life. If 
there is degeneration, it has commenced invisibly long before 
those outward manifestations in the loss of frontal cirri and other 
appendages; it is ever so with decay. And in referring to 
Maupas’ Stylonicliia series, with its increasing temperature from 
the middle of the period onwards, and bearing in mind the effect 
that temperature has on the rate of fission, Biitschli is only 
asking a common-sense question when he demands how, under 
these conditions, it could have been possible to recognise a gradual 
ebb in the fission-energy, such as we may suppose to constitute 
the initial stages of degeneration. Joukowsky, then, found no 
degeneration in his eight-months cultured Pleurotricha. He never 
saw the disappearance of the frontal membranellae : he found no 
abnormal relations in the condition of the nuclei, unless in two 
cases, when a certain change in the relative positions of the two 
parts of the macronucleus was noted. He examines Maupas’ 
Stylonicliia table, and finds that the creature multiplied much more 
quickly in the later weeks,* and to this he in large part attributes 
the degeneration. “It is very possible that the cause of the 
degeneration which Maupas observed is not the mere number of 
generations alone, but the number of generations in association 
with the rapidity of multiplication.” Bor my own part I have 
looked for evidence of degeneration throughout 3-4 month slide 
cultures! of both the Paramecia and Stylonicliia pustulata , as also 
in the case of other odd forms that I happened to find in quantity 
previous to an epidemic of conjugation, but have not recognised it 
in such specific manner as nuclear degeneration or loss of external 
* Some four or five times every 24 hours in place of the normal twice~or 
thrice. 
t In some cases these covered the period of eugamy as calculated by 
generations. 
