THE PROGRESS OF SCIENCE. 



445 



which have been too much neglected by 

 later observers. 



The geologists were especially inter- 

 ested in a paper by Prof. Frank D. 

 Adams, of McGill University, which 

 gave the results of an investigation on 

 the flow of rocks when subjected to 

 pressure in the laboratory under condi- 

 tions which reproduce those obtaining 

 in the deeper portions of the earth's 

 crust. Marble was the rock on which 

 most of the work was carried out, but 

 harder rocks, such as granite, are now 

 being studied. Small columns of marble 

 were carefully turned, polished and ac- 

 curately fitted into heavy wrought iron 

 tubes, constructed on the plan of heavy 

 ordnance by wrapping strips of wrought 

 iron around a core of soft iron and weld- 

 ing the whole together. The core of 

 iron was then bored out and the marble 

 substituted for it. Heavy steel pistons 

 were fitted into each end of the tube, 

 and the rock was submitted to very 

 high pressure, often for several months 

 continuously, in especially constructed 

 machines capable of developing pres- 

 sures reaching nearly a hundred tons to 

 the square inch. Under high pressures 

 the marble was found to flow, bulging 

 out the iron tube that enclosed it on all 

 sides. When the iron tube was cut 

 away a solid block of marble was ob- 

 tained, which had completely altered its 

 shape. It was found, however, that the 

 marble in these cases was only about 

 half as strong as the original rock. 

 Other columns of marble were heated to 

 temperatures of 300° C. and 400° C, and 

 while thus heated the pressure was ap- 

 plied as before. Under these conditions 

 the rock was found to flow readily and 

 to retain its strength much better, being 

 nearly as strong as the original rock. 

 In the third series of experiments, the 

 marble was not only heated to the tem- 

 peratures before mentioned, but at the 

 same time water under a pressure of 

 460 pounds to the square inch was 

 forced through it while it was being 

 compressed. Under these conditions, 

 the marble, after being molded, was 



found to be as strong as it was original- 

 ly. A microscopical study of the struc- 

 ture of the deformed marble shows that 

 in these two latter cases the crystalline 

 grains composing the marble had glided 

 on one another. 



Among the papers presented before 

 the Bacteriological Society one of the * 

 most interesting was by H. L. Russell 

 and S. F. Babcock, of Madison, Wis., 

 upon the causes effective in the pro- 

 duction of silage. The very great in- 

 fluence of bacteria in natural processes 

 has led in the last few years to an as- 

 sumption on the part of bacteriologists 

 that these micro-organisms are agents 

 in nearly all the general processes of 

 nature involving chemical change. 

 Among other phenomena connected with 

 agriculture, it has been claimed that 

 the changes which take place in corn 

 fodder in the farmer's silo are the re- 

 sult of the growth of bacteria. These 

 changes are accompanied by a rapid 

 heating of the material when first placed 

 in the silo and, later, by the production 

 of peculiar flavors and aromas. These 

 phenomena are so similar to those which 

 bacteria are known to produce that it 

 has been a very natural assumption that 

 they are caused by micro-organisms. 

 Russell and Babcock have been of the 

 opinion that bacteriologists have gone 

 too far in ascribing natural phenomena 

 to bacterial agencies, and that it 

 is necessary to look in different direc- 

 tions for the explanation of some of 

 them. The production of silage, for ex- 

 ample, they insist, is not the result of 

 bacterial action. By carefully performed 

 experiments they succeeded in produc- 

 ing normal silage under conditions in 

 which bacterial growth was prevented. 

 They conclude that the changes occur- 

 ring in silage are produced partly by a 

 continuation of the respiratory activities 

 of the plant cells, which, for a time, are 

 stimulated rather than checked when 

 the plants are cut to pieces for storing 

 in the silage, and partly as the result 

 of the action of certain chemical fer- 

 ments or enzymes, which are eliminated 



