NOTES AND MEMORANDA. 
203 
observe before the complete publication of the preceding facts in the 
‘ Archives ’ of Professor de Lacaze-Duthiers.* 
The Li fe-History of a Mimite Septic Organism : ivith an Account of 
Experiments made to determine its Thermal Death Point. — A paper 
under this title, by the Kev. W. H. Ballinger, was read before the 
Royal Society in May last. It was an account of a hitherto unre- 
corded organism, belonging to the septic series, which was found in 
the earlier stages of the decomposition of the macerating body of a 
vole. It was studied by the aid of the “ continuous stage ” used by 
Mr. Ballinger and Br. Brysdale in their “ Researches on the Life- 
History of the Monads,” by means of which a drop of the septic fluid 
containing the organism can be kept under examination for an in- 
definite time, without evaporation ; and be studied with the most 
delicate and powerful lenses. The method pursued was continuous 
study, first of the details of the several metamorphoses, and by the 
light thus gained, a continuous study, subsequently, of their sequences 
in the same individual form. 
The majority of the most difficult and delicate work was done with 
a new ^^^^-inch lens, made for the author, with a special view to this 
class of observation, by Messrs. Powell and Lealand. 
The organism never exceeds the diameter ; 
it is oval, with a constriction slightly in front of its short diameter ; 
and at its anterior extremity has a head-like protrusion, to which is 
attached a long delicate flagellum. At the sides of the shorter, or 
front segment of the oval, somewhat in the position of “ shoulders,” 
two long fine flagella proceed, and as a rule trail with exquisite grace 
behind ; one on either side. It swims with great rapidity and has 
every variety of motion in the fluid ; and in the accomplishment of its 
evolutions its lateral flagella are largely concerned. But besides its 
swimming power, it has the capacity to anchor both its trailing flagella 
to the floor, or the stage, or to a decomposing mass, and by coiling 
these flagella, and bringing itself down upon the body to which it is 
anchored, and then suddenly darting up so as to make its flagella, 
together, the radius of a circle, it darts down on the decomposing sub- 
stance, and by the enormous numbers that are constantly doing it, 
aids in the rapid breaking up of the tissues. 
By steadily following it in the free-swimming condition it was 
seen to undergo fission or self-division, which was a very complex and 
extremely delicate process ; the division beginning in the front 
flagellum and proceeding until, by longitudinal division, a new lateral 
flagellum was, in the act of self- division, made for each half; and by 
the snapping of this both halves went free as perfect organisms, soon 
to commence the process again. A great deal of close and careful 
detail was given of this process, and was accompanied by illustrations 
drawn from nature. There were also accounts of a series of observa- 
tions on the frequency of the recurrence of the process of fission, by 
the continual following of one segmental product of the act ; and 
also, from its beginning to its cessation, in a series of separate 
* ‘ Comptes Rendus,’ vol. Ixxxvi. p. 1557. 
Q 2 
