[scarth] changes in FORM OF CHLOROPLASTS 55 



or even reversible. Mechanical injury gives a markedly fluid effect 

 on the chloroplasts of Spirogyra. 



The resemblance between the movements here studied and the 

 complex evolutions of the chromatic figure in mitosis, e.g., in the 

 shortening and thickening of the spireme and its tendency at one 

 stage to form a spiral suggests that a similar physico-explanation 

 might be found for these mysterious phenomena of life. Chambers'^ 

 work again, in his discovery that chromosomes may be artificially 

 produced, gives strong support to this view. But to arrive at the 

 cause of such movements there seems to be much promise in the 

 experimental method here adopted of treating with precipitating 

 agents and ultra-microscopically studying the results. 



References 



iDe Vries Hugo: Ueber die Contraction der Chlorophyllbaender bei Spirogyra. 

 1889. 



^Loew, Oscar: The Physiological rôle of Mineral Nutrients. U.S. Dep. of 

 Agric, Div. Veg. Phys. and Path. Bull. 18, 1899. 



'Osterhout, W. J. V.: Specific action of barium. Amer. Jour. Botany, ç: 

 481-482. Nov. 1916. 



^Chien, S. S. : Peculiar effects of barium strontium, and cerium on Spirogyra. 

 Bot. Gaz. 63: 406-409. 1917. 



^Kite, G. L.: Studies on the physical properties of protoplasm. 1. The physical 

 properties of the protoplasm of certain animal and plant cells. Am. Jour. Physiol. 

 32: 2, p. 161. 1913. 



^Schroeder, P. von: Erstarrungs und Quellungserscheinungen von Gelatin. 

 Zs. Physik. Chem. 45: 75-117. 1903. Viscosity of gelatine sol passes insensibly 

 and progressively into that of gel. 



'Chambers, R., Jr.: Micro-dissection studies. I. The Visible Structure of 

 Cell Protoplasm and Death Changes. Am. J. Physiol. 43: 1-12. 1917. 



^Chambers, R., Jr.: Micro-dissection studies on the physical properties of 

 protoplasm. Lancet Clinic. Mar. 27, 1915. 



«Lloyd, F. E., and Scarth, G. W.: An Introductory Course in General Physi- 

 ology. Montreal, 1921. 



