14 CHAP. II. HIGH MAGNIFICATION CRESCOGRAPH 



taken. The increase or diminution of the space between 

 successive dots in the second record, as compared with the 

 first, at once demonstrates the stimulating or depressing 

 nature of the changed condition. 



Moving Plate Method. — The smoked glass plate in this 

 case, as already stated, is carried laterally past the 

 writer. The record is now a curve, the ordinate represent- 

 ing growth-elongation and the abscissa the 

 time. The increment of length divided by 

 the increment of time gives the absolute rate 

 of growth at any part of the curve. As long 

 as the growth is uniform, so long the slope of 

 the curve remains constant. When an agent 

 enhances the rate of growth, there is an up- 

 ward flexure in the curve ; a depressing agent, 

 on the other hand, lessens its slope. 



Determination of Absolute Rate of 



Fig. 4^. Cresco- GrO\VTH 



graphic records. 



I7y^piatto*f?he Experiment i.— The record of growth 

 absolute rate of obtained with a vigorous specimen of 5. 



srrowth. Second _^ , , . . , . . 



record taken Kysoof ou a stationary plate is given m 

 after 15 min- f^^ . -pj^g oscillation frequency of the 



utes. Magnifi- o t -^ j 



cation 10,000 plate w^as once m a second, the magnm- 

 times.(Kysoor.) (.^^jqj^ employed being 10,000 times. The 



magnified growth-movement was so rapid, 

 that the record consists of a series of short dashes instead 

 of dots. 



After the completion of the first vertical record, a second 

 record was taken after an interval of 15 minutes. The 

 magnified record for 4 seconds is 38 mm. in the first record : 

 it is precisely the same in the record taken 15 minutes 

 after. The growth-elongation during successive intervals of 

 I second is practically the same throughout, being 9-5 mm. 

 This uniformity in the spacings demonstrates not onl}^ the 

 regularity of growth under constant conditions, but also 



