820 EXPERIMENT STATION EECORD. 



whether or not the present methods of disinfecting seeds are adequate to fur- 

 nish material safely free from such infection. Lots of 25 each of the seeds of 

 white lupine, peas, wheat, barley, corn, and white mustard were used in the 

 experiments, similar lots in each case being treated for various lengths of 

 time with each of the following disinfectants: Cleaning fluid, mercuric chlorid, 

 hydrogen peroxid, potassium bichromate, ammonium persulphate, bromin water, 

 and formaldehyde gas, on dry seeds and on seeds soaked in water for 5 minutes. 

 In the first series of experiments the efforts were directed toward determining 

 the length of time each kind of seed could be left in each one of the disinfect- 

 ants and still yield from 70 to 80 per cent of good seedlings. The second series 

 was used to determine the effects of the different treatments on the fungi and 

 bacteria when applied for as long a period as had been found to be safe. 



The results obtained by the author are rather strikingly opixised to those of 

 other workers, showing quite uniformly a failure to destroy the contaminating 

 organisms within the periods of safety to the grains, except in a few instances. 

 Of the 48 lots tested only 2 lots of white mustard and 3 lots of white lupine 

 were completely freed from bacteria and fungi. The only disinfectants wholly 

 successful in this respect were cleaning fluid and peroxid of hydrogen. Bromin 

 water was successful in the case of white lupine. 



The author concludes that the majority of cases of so-called disinfection 

 are merely cases of antisepsis, and that antisepsis and not disinfection must 

 probably be looked to for practical results in the future. This he claims will 

 ordinarily suffice, since in most physiological experiments it is not the mere 

 presence of dead or dormant organisms in or on the grains, but their active 

 growth and multiplication, that impairs the value of the results. Absolute dis- 

 infection, which seems out of the question at present, is not considered essen- 

 tial in most cases. 



An extensive bibliography is appended. 



The persistence and vitality of bacteria on alfalfa seed, M. J. Pbucha 

 (Ahs. in Science, n. ser., 35 (1912), No. 803, p. 229). — Attention is called to the 

 difficulty of sterilizing seeds such as wheat, corn, peas, alfalfa, etc., without 

 killing them. It has also been found that bacteria of disease are carried on 

 beans and corn, and the author conducted experiments to determine to what 

 extent bacteria may persist on seeds. 



Quantitative and qualitative studies were made of 19 samples of alfalfa 

 seed, grown and collected in 1909, from 11 different States. The study was 

 pursued for 2 years. In the fresh seed the bacterial content varied from 12 to 

 16,000 per seed. With increasing age the germ content decreased. A typical 

 sample which when fresh had an average of 7,780 bacteria per seed, at 2 years 

 of age gave 340 bacteria per seed. 



Of the 84 different group numbers determined, 35 were Bacillus, 21 Bac- 

 terium, 19 Pseudomonas, 1 Streptococcus, and S yeasts. 



The influence of lig'ht on the germination of seed, W. Lttbimenko [Rev. 

 G^n. Bot., 23 (1911), No.27Jf, pp. 418-436, dgms. 2; abs. in Trudy Imp. S. Peterb. 

 Obshch. Estestvo. (Trav. Soc. Imp. Nat. St. Petersb.), 42 (1911). I, No. 3, pp. 

 142, 152, 153). — Studies were made of the germination of the seeds of Pinus syl- 

 restris, C'aragana arborescens, Bettda alba, and Picea excelsa in different con- 

 ditions of light and darkness. 



The author found that from a physiological standpoint it is necessary to dis- 

 tinguish two types of germination, one germination in the light and the other 

 in darkness. For the first type of germination light is believed to play a stimu- 

 lating effect, and the maximum germination is attained under an optimum 

 illumination. For the second type light has a retarding and sometimes a detri- 

 mental effect unless it is very feeble. In the first class P. si/lv8St)-is and B. alba 



