The San Francisco call., 1896-05-31
Dr.. Jerome A. Anderson
On It's Importance.


mosphere and centrosomes with the centric
sphere is not always plain. 1t would be incor-
rect to state that the centrospnere surrounds
the somosphere, as frequently the somosphere
is seen TO lie at one edge of the centrosphere.
While the plasmocy toblastis in resting stage
could frequently detect several darker gran
ules in the somosphere, and which, judging
from more advanced plasmocytoblasts proba-
bly, never exceed three or four in number. AT
least have never, with any certainty. found
more than four centrosomes in any plasmo-
cytoblast, and rarely more than three.
DEVELOPMENT OF THE PLAsMoCYToBLAsTS.-
1 have already pointed out that by arranging
a series of drawings of the plasmocytoblasts
it soon becomes evident that they are in
different stages of development. Not only are
some much larger than others, but these larger
ones show division of the inner spheres. And
this division appears to be caused by the
separation of the centrosomes, carrying with
them each one an envelope of one or two
spheres. further stage yet and this grano
sphere surrounds itself with e shell OF hyalo-
sphere and plasmosphere.
No CELL MEMBRANE.-The plasmocytes are
not surrounded by any cell membrane, the
outer zone plasmosphere being entirely
uncovered. could not find any signs of the
formation OF new membrane except in one
or two instances In this ins tance the plasmo-
cyte was so rounded and the plasmosphere
showed no smeboid projections. thin
membrane bounded the sphere outwardly.
Another point of considerable interest is,
Eave observed. concerning the staining of the
endoplasmic sphere. When there are two dis
tinct divisions of the centrospheres or of the
granospheres. one frequently stains different
from the other.
The final effort of the centrosome appears to
me to be to separate itself entirely and to form
the center of plasmocyte. But if such sep
aration takes place, as 1 know it does, it is
mostly confined TO the pIasmocytoblast and
| cases very pale and unstained, while the GEN.
trosomes very sharply defined. In order
not to repeat myself too much 1 will not now
describe the respective figures or discuss the
variations of the respective spheres.
Concerning the final Enclosures of the cen
| trosomes, 1 can only say that they vary to
| considerable extent as regards location. But
have frequently seen them lying in half-circle
and connected by a thin somosphere. Or the
division may be more perfect. in which case we
find three distinct centrospheres, each with a
| centrosome.
/, The new element has increased in size, and
as it has moved away it has also changed its
form. The various envelopes of the new plasmo-
| cyte do not show bearing apart and an irreg-
ularitv OF form, but show surprising regular
! fty, or as much as could be expected in any
element. But moreover, the final step in the
development of the plasmocytoblast is to sur
round itself with regular and complete COW
ering of the exterior zone, the plasmosphere.
1t is the closing of this sphere which decides
the time when the new element, the plasmo-
| cyte. is complete.
THE PLAsMocYTEs.-In the foregoing I have
set forth how the inner spheres of the plasmo-
cytoblasts have gradually reeeded from the
immediate vicinity of the nucleus how they
have clothed themselves with envelopes of the
outer or ectoplasmic layers, and finally how
they have entirely separated themselves from
the fusiform eorpuscles existing as new ept
ties in the blood serum, with all signs of in.
crease in size, assimilation of food, or phogo
cytosis, exhibiting ameboid movement just
as the originally independent leucocytes.
GROWTH OF THE PLAsMoCYTEs.-While large
number OF plasmocytes are not any larger
than the largest divisions of the plasmocyto-
blast many of them are much larger, and from
this 1 draw the conclusion that they must
have grown. Between these the largest plas-
mocytes and their yet attached progenitors
there are all possible grades. have seen plss
mocytes which were as large as the nucleus OF
the erythrocyte. The majority however, are
much smaller as will be seen by the measure
ments given below.
This growth must be caused by the assimlla
ton of food of various kinds. Probably mos
of the food supply is derived from the blood
serum direct, but some of it at least is at
!
Thus 1 have found many times plasmocyte:
which had engulfed small erythrocytes-ot
course only those of the smallest kind. Thil
is especially interesting because we find en-
closed in the erythrocyte parasitic protozoa
the life history of which have made out L
is not difficult to see it if we have an instance
of phogocytosis, or if simply one blood ele
ment has been superposed on the other, as fre
: ouently occurs. l find repeatedly plasm ocyte
, I,,-hf fah lia an ton af q rcd
would at hasty examination appear as
, the plasmocyte was inclosed in the former
But when simple overlapping occurs l finC
that there is always halo around the edges
of the superposed element, caused by the press
ing back OF the protoplssm OF the underlying
one. In case of real phogocytosis this hall
never occurs.
From the foregoing observations it will b
seen that in the fusiform elements, of the bloo'
at least the eentrosomes, or perhaps the mi
' crocentrum-as we cannot well separat
/ them-show an independent life history an
: life; surviving, growing and changing lon
8 after the other constituents OF the cell hav
D disintegrated as such. AS far as can see tn
plasmocyte occupies the same position a
would real cell, showing with it all the ger
eral Qualities of the cell as understood b
modern cytologists, except one, the power
produce new cells At least, no instance of ur
qualified plasmocyte division has come unde
my notice. The question now arises, in whs
relationship stands the microcentrum, or tn
centrosome, to the nucleus and the center {
the cell? As is well known, there are two oppC
site views this matter.
One regards the centrosome as an origins
constituent of the cell always present and {
paramount Importance to the life history
the cell. The adherents of the other theor
claim that the centrosome is only an organ {
the cell, like the heart of the animal bod!
either always present or temporarily create
at the time of mitosis or cell division.
According to the latter theory the only fun
ton of the centrosome and mierocentrul
would be to carry off and mechanically diret
the complicated forces of mitosis, and whe
this is accomplished the function would h
gone.
This theory would suffice as long as centr
somes were not found in cells which had lo
their power of mitosis, or at least would nevt
again divide by kanyokinesis.
will now point out that if we not only re-
ognize that probably the microcentrum
always present in every cell, but also ca
prove that the microcentrum In son