FEBRUARY 2, 1912] 
the cells of the crown-gall motile, flexuous, 
rod-shaped bodies which I take to be this 
organism, and we have occasionally stained 
in small numbers in the cells bodies which 
closely resemble rod-shaped bacteria, but 
ordinarily they occur in such small num- 
bers or take stains so vaguely and imper- 
fectly that this method of demonstration 
would not be convincing to an outsider. 
Also sometimes we find small groups of 
cells filled with what appear to be semi- 
disorganized bacteria, as if here the bac- 
teria had gained the mastery for a short 
time and then degenerated. We have not 
in the whole eight years obtained any very 
satisfactory slides, although many attempts 
have been made, using a great variety of 
fixing agents and of stains. As I have 
stated elsewhere, if we had depended on the 
microscope alone we should not have been 
able to work out the etiology of this dis- 
ease, and the plain demonstration of the 
parasite in the cells must await, I think, 
the development of some special technic of 
staining whereby we may be able to mor- 
dant the bacteria in such a way that they 
shall take one color while the contents of 
the host cell takes another. Even in case 
of the Y-shaped bodies one is seldom able 
to demonstrate them in the stained cells. 
We have obtained the best results by an 
indirect method, namely, by taking clean 
slides and burning the surface free from 
all possible organisms, then putting on a 
little distilled sterile water, and putting 
into this sections of young crown-galls 
taken from a portion of the tissue pared 
free from all exterior parts, allowing the 
contents of the cut cells to diffuse into the 
water for-an-hour, then removing the sec- 
tions, drying the fluid and staining the 
slide. Examining such slides under the 
oil-immersion objective in course of a day 
one finds a good many such Y-shaped bod- 
ies. We have found the best method to be 
SCIENCE 
171 
the systematic search of the whole slide, 
passing it back and forth under the objec- 
tive. Searched in this way, about one field 
in four yields a Y-shaped body. Bacterial 
rods have also been obtained from the 
tissues in this way. 
Various researchers on cancer have men- 
tioned finding rod-shaped and Y-shaped 
bodies in cancer cells. For example, Dr. 
Borrel, of the Pasteur Institute in Paris, 
and Dr. Reese, working in the cancer lab- 
oratory at Buffalo. 
These plant neoplasms contain both small- 
celled and large-celled parenchyma and a 
variety of other tissues, e. g., vessels and 
fibers. Cell division is sometimes so rapid 
that the cell wall can not keep pace. 
(Slides shown.) Frequently two and some- 
times more nuclei are present in a cell. A 
portion at least of the cell divisions are by 
mitosis; but not all, it would seem. Some 
queer things take place in the cells. We are 
now studying the mechanism of cell-division 
in these tumors and are not ready to report. 
To conclude, suppose we had in human 
cancer as its cause a microorganism multi- 
plying in small numbers within the cell, 
having a definite action on cell nuclei, 
readily inhibited by its own by-products, 
losing virulence easily, passing quickly 
‘over into involution forms which are diffi- 
cult to stain, and which are so paralyzed 
that only a very small portion will grow at 
all, except from the very youngest cells, 
and these only after a considerable period 
of time has elapsed, and further suppose 
that for their growth some very special 
technic of isolation, or some peculiar kind 
of culture media were necessary, then we 
should have precisely the same difficult 
conditions of isolation and determination 
as have confronted us in case of this simi- 
lar overgrowth of plants, and ample ex- ° 
planation of why expert animal patholo- § 
gists have been unable to see the parasite 
