ANIMAIv PARASITES INOCULATED INTO PLANTS. 179 



of beans and peas. His method was to wash the surface with mercuric chloride water, then with 

 sterile water, after which a longitudinal incision was made with a sterile knife, the wound pried apart 

 a little and the platinum needle carrying the infectious material introduced. Unlike Kornauth and 

 Kasparek he did not cover the wound with collodion but left it exposed to the air so as to have the 

 conditions as nearly as possible like natural conditions. He states that the organism remained alive 

 in wounds for a long time and multiplied. When the seeds were wounded most of them passed over 

 into a slimy rot which contained for a long time extremely well developed living bacteria of the form 

 introduced. Bacteria from these wounds produced the typical disease when inoculated back again 

 into animals (white mice and finally guinea pigs). In the dried parts both of stems and pods, the 

 organism in its resting form was found to be alive and infectious to animals at the end of 6 months. 



"The inoculation cuts had for the most part a rusty brown appearance [host reaction], but not 

 rarely in some cases there was also a slight accumulation of the slimy substance to be observed which 

 was found to be an aggregation of bacteria into a slimy mass. " 



His conclusions are as follows: 



(i) Our bacterium cultivated upon acid nutrient media can develop further in living plant parts. 



(2) It is capable of remaining alive not simply for a short time, but even upon dead plant parts with the help of 

 its resting forms, perhaps to maintain a prolonged capability of growth, without actually penetrating directly into the 

 cell-tissue and multiplying inside of the same. 



(3) That, in consequence of this preponderating parasitic manner of life, it is able, when carried back to animals 

 to cause the infection and death of the same. 



It is stated that the organism was also cultivated on carrots, both sterilized and unsterilized, 

 where it formed at first a slime, and afterwards a dry layer, and in one instance a guinea pig was 

 infected by feeding upon such carrots. The inoculated parts of the plants either healed over with 

 more or less callose, or else there was a direct death of the cell-tissue in the vicinity of the wound. 

 Generally the organism appeared in unmixed growths in the wounds, sometimes in vegetative forms 

 as rods, and sometimes in the resting form. Only scattering wild yeast-cells accompanied it. 



Hartleb states that the cultures he used had lost most of their power to destroy animals and 

 consequently this passage through plants increased their virulence. Just what he worked with is 

 not apparent, as the cause of the foot and mouth disease is still believed by most pathologists to be 

 undetermined and probably ultra microscopic (Vide KoUe und Wassermann, Jena, 1904, Bd. IV, 

 2ter Teil, p. 1325). 



Laurent (1899) maintained that he was able by special treatments to cause Bacillus 

 coli to become a plant parasite, but this claim is still disputed . In this connection see page 4 2 . 



John R. Johnston working in the writer's laboratory on the coconut bud-rot of the 

 West Indies has obtained evidence that it is due to an organism indistinguishable from 

 what ordinarily passes for Bacillus coli (Phytopathology, Vol. I, No. 3). 



EUrodt's paper (1902) relates to the possible transmission of human and animal 

 parasites by means of plants. He states that Bacterium pyocyaneum can enter plants 

 through wounded roots, but not through sound ones. This conclusion rests on the follow- 

 ing experiments. 



In a series of flower pots, oats, beans, vetches and peas were planted. When these were about 

 20 cm. high, the earth was watered with a suspension of Bacterium pyocyaneum. The same experi- 

 ment was undertaken with Viola odorata, Paeonia officinalis, and Iris sibirica. Cultures were made 

 the next day by cutting out a piece of the plant with sterile knives, thrusting a platinum needle into 

 the exposed tissues and streaking the sap on agar and glycerin agar. As the cultures gave absolutely 

 negative results, the earth was again wet with a bacterial suspension of the organism, and after 4 or 5 

 days streaks were again attempted on agar in the same manner. These likewise remained sterile. 

 Samples of the soil, on the contrary, yielded numerous colonies of Bacterium pyocyaneum. 



Erlenmeyer flasks containing a culture fluid of the following composition: distilled water 1000; 

 asparagins; sodium acetate 5 ; potassium phosphate 2 ; sodium chloride 2 ; magnesium sulphate o.i, 

 were now inoculated with Bact. pyocyaneum, and incubated for 5 days, during which time there was 

 luxuriant growth and appearance of the characteristic blue-green color. Bean plants taken from 

 pots were now introduced into this fluid. After some days leaves were cut off with a sterile knife, a 

 platinum needle was thrust into the leaf-stalk, and streaks were made on glycerin agar. These 

 remained sterile. Some days later the cultures were repeated, being taken this time from the interior 

 of the stem at 15 cm. from the roots. One plant yielded a pure culture of Bact. pyocyaneum. Those 



