6 CHEMICAL AGENTS AND PROTOPLASM [Ch. I 



protoplasm appearing hyaline. The living substance is in 

 repose. The hydrogen may be passed through the apparatus 

 containing the stamen hairs for from 1 to 5 hours without any 

 movement or other change appearing in the protoplasm. Air 

 is now admitted. The protoplasmic movements rapidly return ; 

 the granules at first oscillate in their places, then gradually 

 extend the range of their movement. In 5 to 6 minutes the 

 cell has regained all of its anatomical and physiological charac- 

 ters. A similar immobility affects also leucocytes subjected to 

 hydrogen. This occurs in about an hour; but there is great 

 individual variation in this respect. Upon substituting air, 

 the activity of the protoplasm is resumed in from 10 to 20 

 minutes. Protoplasm which has been subjected to the action 

 of hydrogen thus appears not to be permanently modified, since 

 normal movements recur rapidly upon readmitting air. It 

 seems probable, therefore, that the temporary cessation in move- 

 ments in the presence of hydrogen is due to the exclusion of 

 oxygen from the protoplasm. 



3. The two Oxides of Carbon, COj and CO, have very dif- 

 ferent effects upon protoplasm. Thus Demooe ('94, pp. 191, 

 202, 219) found that whereas the former immobilizes quickly, 

 but kills very slowly, perhaps chiefly by asphyxia, the latter 

 seems in some cases actively to attack the protoplasm. In 

 leucocytes, the ectosarc is separated from the endosarc in a 

 number of completely hyaline fragments ; the endosarc becomes 

 vacuolated, and death ensues in from 20 to 60 minutes. Many 

 bacteria are only slightly affected by CO. 



4. Ammonia (NHg). — A 10% solution provokes vacuoli- 

 zation, partial coagulation, and irregular movements in the 

 protoplasm of the Tradescantia hair. The cell finally enters 

 into repose, all the granules accumulating around the nucleus. 

 Washing the preparation with water restores the original char- 

 acters of the protoplasm. Thus, ammonia at first energetically 

 excites protoplasm, later producing anaesthesia. (Demook, '94, 

 p. 193.) Even with very weak aqueous solutions (0.005%), 

 which do not kill the protoplasm, BoKOiiNY ('88) has observed 

 the production in Spirogyra cells of granules, which process 

 does not, however, seem to modify the normal activities of the 

 cell. These granules, " proteosomes," are intensely blackened 



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