THE ITALIAN DISEASE OF STOCK. 279 



The infection rapidly spreads on the leaves and branches, extending to the inflorescence, which 

 dries up completely. The plants can throw out other floriferous branches, but of poor development 

 and with few flowers. 



We tried also infection through the roots, bathing with a pure-culture solution the soil of some 

 pots in which were healthy plants, but not a single sign of disease was observed at the end of two 

 months. For the infection of the roots perhaps wounds are necessary. 



We are able to establish that the more common manner of infection is through the stomata, as 

 plainly shown by the pale yellow coloring which spreads from the stomata to the surrounding cells, 

 in which we observed the usual disorganization of the chloroplasts and of the protoplasm. 



From the organs infected artificially we repeatedly made cultures in various nutritive media 

 for the identification of the morphological and cultural characters of the microorganism of our 

 preceding isolation and description. 



This organism must be regarded as a new species, to which is given the name Bacterium mal- 

 tliiolac n. sp. 



The same year Briosi and Pavarino published a second paper (Bacteriosi della Matihiola 

 annua L-), which is exactly the same as the one just reviewed, except for the following 

 additions : 



The stab growth in plain agar is described as ciliated (cigliato). 



. 1 gar plates. (Natural size.) After 48 hours' incubation the surface colonies are round, margins 

 smooth. They are slightly raised, but not transparent, and of a whitish color. The buried colonies 

 may be roundish, but for the most part have the form of a whetstone. 



Enlarged 30 diameters. The surface colonies appear roundish, radiate, with transparent contour, 

 and of a yellowish color. The buried colonies may be roundish, but for the most part are like a whet- 

 stone, always smaller and of a darker yellow color. 



Under plain broth the sediment is described as viscous. 



Milk-cultures. At a temperature of 30 C. the coagulation is complete on the third day with 

 decidedly acid reaction to litmus. 



Specific and practical methods for the cure of this disease are unknown. We made tests with 

 the usual sprays, using copper sulphate as the base (Bordeaux mixture), but the results obtained 

 were negative. Perhaps such treatments might be effective applied as preventives sometime before 

 the flowering period, with additional sprayings afterward. 



A good practice to follow is that of extirpating the plants as soon as they present the symptoms 

 of the disease. 



The extirpated plants should not be permitted to accumulate on the land, where when dried 

 they can be easily transported to a distance by the wind or by animals, but should be carried out 

 of the field and destroyed by fire. Likewise, in order to prevent the infection being carried back 

 by means of stable refuse, these extirpated plants must not be thrown on the manure heap. 



The rotation should be modified so that the culture of the stocks is not repeated on soil where 

 the disease appeared the preceding year. To prevent the disease being transmitted from one 

 year to another, it is rather useful to employ accurate seed selection, using only seed that has come 

 from healthy plants, and from fields remaining immune to the infection. And since it has been 

 demonstrated that germs of bacterial diseases frequently are able to continue to live on the seed 

 during the winter season, it would be useful also in the present case to disinfect the seeds, immersing 

 them for 15 minutes in a solution of 1 :iooo mercuric chloride, or in a solution of formalin 1 150 for 

 20 minutes. This practice ought to be completed by the selection, according to the method of 

 Nilsson, in the field of those individuals which show more resistance to the disease. Finally, it 

 would, perhaps, render the plant more resistant to the disease to avoid abuse of organic fertilizers, 

 and to have recourse to use of potassium fertilizers, and especially the superphosphate. 



The writer has had no opportunity to study this disease at first hand. Some samples 

 of stock supposed to show this disease were received from Italy, but it proved to be some- 

 thing else. 



LITERATURE. 



1912. Briosi, G. and Pavarino, L. Una malattia 1912. Briosi, G. and Pavarino, L. Bacteriosi della 



batterica della Matihiola annua L. (Bac- Matthiola annua L. {Bacterium matthiolae n. 



terium matthiolae a. sp.). Atti della Reale sp.). Atti dell' Istituto Botanico della R. 



Accademia dei Lincei, Rendiconti, vol. xxi, Universita di Pavia, Serie II, vol. xv, Milano, 



Fasc. 3, Rome, August, 1912, pp. 216-220. 1912, pp. 135-141, 2 pis. (colored). 



