PROTOPLASMIC MOVEMENT. 393 



rapid it would be at once destroyed. It appears that in such a 

 case no corresponding strong contraction takes place. 



In sea-water which I had preserved for more than a year, 

 and which by gradual evaporation had become so concen- 

 trated that there was 10 per cent, of saline matter, numerous 

 Protozoa, even Worms, Arthropods, Diatoms, Green Algae, 

 &c.,^ still lived and apparently quite comfortably. I was also 

 able to repeat Czerny^s^ experiment with fresh-water Amoebae, 

 and accustom them in the course of several weeks to 4 per 

 cent, solutions of common salt. "With the action of 10 per 

 cent, solution of common salt, according to Kiihne,^ fresh- 

 water Amoebae immediately pass into spherical bodies which 

 quickly break up and throw out a network of fine mucous-like 

 threads, while the rest passes into the form of coarser and finer 

 particles which move about with active molecular movement. 

 Salt-water Amoebae behave in a similar manner. 



3. Oxygen. 



In media quite free from oxygen spontaneous movement 

 can without the least doubt only go on for a short time — 

 at most for some hours. The gradually advancing cessation 

 can always in its early stages be stayed by the admission of 

 oxygen, and indeed in this way only. "With regard to the con- 

 nection between the energy of the movement and the amount 

 of the absorption of oxygen in the surrounding media, only so 

 much can be said with certainty, that the movement in many 

 (all ?) cases is a permanently maximal one at very slight pres- 

 sures, far under the normal. At great pressures of oxygen 

 (3 — 6 atmospheres) it diminishes, but is accelerated when the 

 pressure is lowered again. 



Evidently the living protoplasm enters into chemical union 

 with the surrounding media, and the oxygen thus firmly com- 



J Cf. also Dutrochet, ' Compt. rend.,' 1S37, ii, pp. 7S1, 7S2. 

 ' V. Czerny, 'Arch. f. mikr. Anat.,' v, p. 15S, et seq., 1S69. 

 ^ Kiihue, ' Unters. iiber das Protoplasma, &c.,' p. 4S ; cf. also Czerny 

 and others. 



