26 MARY DRUSILLA FLATHER. 



important factor is the specific permeability of the osmotic 

 :nbrane. Degen found that alcohol, ether, acetone and 

 chloroform had a rapid lethal effect but little direct influence on 

 the vacuole. He concluded from his various experiments that 

 the vacuolar membrane has a remarkable physiological, but no 

 morphological differentiation from the surrounding protoplasm. 

 The frequency of the pulse he believed conditioned by the water 

 intake and its osmotic value relative to the environmental fluid. 

 It would seem that any agent as powerful as the glandular 

 extracts should exert a strong influence upon the rhythmic con- 

 tractions and perhaps by means of a specific influence give some 

 important information as to the function of this primitive organ. 

 Some work has been done already on the effect of the extract > 

 upon the general metabolism of protozoa. Nowikoff (22) found 

 that thyroid extract increased the division rate in Paramecium. 

 Extract of hypophysis had no such effect. Calkins (4) obtained 

 no reactions with pancreatic extract. Shumway (26) confirmed 

 Nowikoff 's observations, finding that thyroid extract was the 

 only glandular product producing any significant increase in 

 division rate. He also noted a tendency toward the formation 

 of extra vacuoles and an increase in pulse frequency. Chambers 

 (5) found that a solution of suprarenal extract with a basic fluid 

 of either hay infusion or malted milk produced an increase in 

 division rate, while a solution of pituitary, Armour & Co. tablets, 

 produced no influence with malted milk and only a very slight 

 increase in division rate with hay infusion. A mixture of pitui- 

 tary and suprarenal solutions in the basic food substance appeared 

 to reduce the division average. 



In October, 1918, the following experiments were started to 

 determine the specific influence of adrenalin, pituitary subi-t.ince 

 and pineal gland extract upon the contractile vacuoles of Pam- 

 mecium caudal uni. Individuals for the experiment were t.iken 

 from wild cultures just introduced into the laboratory. First 

 a number of observations were made upon pure line cultmv- t<i 

 determine whether or not there might be, (i) any significant 

 variation in the pulse frequency of individuals in different pure 

 lines kept in the same physiological environment, <-> any sig- 

 nificant similarity in the pulse frequency of individuals in the 



