i^ô THE ROYAL SOCIETY OF CANADA 



of various reagents upon the swelling of the protoplasmic emulsoicis, 

 and whether this can be used in growth. 



The effect of acids. When combined with 20 per cent cane-sugar, 

 acids (hydrochloric, nitric, acetic, citric) produced the following 

 results. At the lower concentrations used (N/51200 to N/3200 incl.) 

 the growth rates were about the same as in the control, at all events 

 no greater. At higher concentrations (N/1600 to N /200) the 

 growth rates were less and less in direct relation to the concentration 

 and always less than in the control, and was terminated by bursting. 

 When however acetic acid was combined with cane-sugar at a con- 

 centration of 40 per cent (this concentration being the control), 

 with the acid component in the above fractional normalities, a maxi- 

 mum growth rate approximately four times that of the control took 

 place in N/3200. Bursting still occurred in N/1600 when the tubes 

 had attained a length of 0-5 unit within an hour. 



The effect of alkalis. The analogous effects of alkalis, as exempli- 

 fied by sodium hydrate, were obtained in very clear cut terms at the 

 lower sugar concentration, viz., 20 per cent. This may be due to the 

 normal acidity of the protoplast. Neutral red allowed the fact of 

 penetration of the alkali to be established^ and this result seems to 

 indicate that the effect of the alkali can not be due simply to the 

 possible hydrolysing effect on the cell-wall, thus reducing its resistance 

 to the growth pressures, if at all. At N/400 the growth was always 

 less than in the controF while at the concentrations N/800 to N/12800 

 it was always greater. The highest rates were found to occur in 

 N/1600 to N/3200, thereabout, being greater as the concentrations 

 were reduced from N/800 to N/3200, and gradually lessened as they 

 were further reduced from N/3200 to N/12800. It must be further 

 noted that the greatest increase in growth rates took place during the 

 earlier growth period, up to the time at which 8 to 10 units of length 

 were attained, and during the first 60 to 80 minutes, before vacuoliz- 

 ation sets in. After this the relations appear to remain comparatively 

 constant. At the higher concentrations bursting took place, as in 

 the presence of acids. 



With a salt (potassium nitrate) no effect on growth rates could be 

 discerned, although only preliminary tests have been made. 



Experiments with gelatine. To what extent may an analogy 

 between the above growth reactions and the swelling of emulsoids in 

 various media be traced ? This question has prompted experimenta- 



'On this see Harvey, E. Newton, .\ criticism of the indicator method, etc. Am. 

 Jour. Phys. 31: 335, Mar., 1913. 



-The experiments ran for about 100 minutes. 



