PATHOLOGY: E. F. SMITH 
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hyd, ammonia, amines, alcohol, acetone, acetic acid and formic acid, to 
which I think I may add traces of CO2. 
These substances, it will be observed, are, for the most part, just 
those compounds which Jacques Loeb and others have observed to be 
the most efficient in starting growth in unfertilized eggs of the sea urchin, 
to wit ammonia, amines and fatty acids (vide Loeb: Artificial Parthen- 
ogenesis and Fertilization. The University of Chicago Press, 1913). 
Their action in all probability is purely physical, that is, due to with- 
drawal of water from neighboring cells by increase of osmotic pressures 
whereupon the cells so acted upon begin to grow, at least it is possible 
to obtain the same phenomenon in plants with a great variety of sub- 
stances, not the product of parasites and not likely to come into con- 
tact naturally with the growing tissues. 
Thus far I have made no experiments with aldehyd or formic acid 
and have only just begun to experiment with acetone, but experiment- 
ing with the other substances named I have obtained from young tissues 
a prompt response in the form of over-growths. At first I used water 
dilutions of these substances painted on or injected, but eventually I 
used their vapors with marked success. The ethyl alcohol, however, 
was used mixed with acetic acid, and I do not yet know its unmixed 
effect. These experiments have been made on several kinds of 
plants subject to crowngall, especially on Ricinus, cauliflower and 
Lycopersicum. 
The tumors obtained have been small because only a single applica- 
tion was made and consequently the stimulus was soon exhausted, but 
there is no reason to doubt that a continued application of these sub- 
stances in high dilution, after the manner of the parasite itself, would 
result in tumors essentially like those occurring naturally in crowngall, 
or resulting from our bacterial inoculations. 
These tumors are either vascularized hyperplasias, mixed hypertrophy 
and hyperplasia, or simple hypertrophies. In them the cells are much 
more closely compacted than the parent cells and free from chlorophyll. 
The cells of the hypertrophies are frequently a hundred times the 
volume of the cells from which they have originated. In the acetic 
alcohol tumors there has been a great increase in the number of the 
cells, i.e., the development of a true hyperplasia, while in the hyper- 
trophies the component cells appear to be the original cells greatly 
enlarged. 
Curious vascular displacements and duplications have also been ob- 
