PROTOPLASMIC MOVEMENT. 395 



of the injurious action towards life of oxygen at high pressures, 

 experimented with this agent. He observed that the colour- 

 less blood-corpuscles of the frog become round and motionless 

 at 3 — 6 atmospheres of oxygen pressure, and resume their 

 movements at ordinary pressures. 



4. Other Chemical Conditions — Poisons. 



Like all the vital phenomena of elementary organisms the 

 spontaneous movements of the protoplasm can only continue 

 for any time when the reaction of the imbibition fluid is 

 neutral or almost neutral. A trifling excess of alkali or even 

 more surely of acid causes a cessation which for a time may 

 be counteracted by neutralization of the excess. 



Dutrochet ^ saw the movement in Chara stop completely in 

 potash solution of 0*05 per cent, in thirty-five minutes, in pot- 

 ash or soda of 0"1 per cent, iu two or three minutes, in tartaric 

 acid of 10 per cent, in ten minutes, of 0"1 per cent, in an 

 hour. 



Max Schultze confirmed the injurious action of diluted acids 

 (hydrochloric, acetic, and osmic) and alkalis on Miliola,^ 

 Actinosphoerium,^ Tradescantia,* Mysomycetes. And 

 Kiihne also on Amoeba/ Actinosphoerium,^ Myxomy- 

 cetes,'' Tradescantia.^ 



In diluted caustic alkali the protoplasm swells up strongly, 

 deliquesces and completely breaks up. Before the cessation 



p. 122, 1876 (Russian). I am acquainted only with Hoyer and Mayzel'a 

 abstract in Hofmann and Schwalbe's ' Jahresber.,' v, 1876, p. 22. 

 1 Dutrochet, ' Compt. rend.,' 1837, ii, p. 781. 



* Max Schultze, ' Das Protoplasma, &c.,' pp. 22 and 37. 

 » Ibid., p. 32. 



* Ibid., p. 42. 



* W. Kiihne, • Untersuch. iiber das Protoplasma und die Contractilitat., 

 p. 49 (HCE 0-1 per cent., KHO 01 per cent., and 1 per cent.). 



8 Ibid., p. 64 (HCE 01 per cent., KHO O'l per cent.. Ammonia Vapour) ; 

 p. 67 (CO2). 



? Ibid., p. 85 (Ammonia Vapour) ; p. 89 (COj). 

 8 Ibid., p. 100 (HCE, KHO). 



