ffUTEITIOJS" OF DHOSEEA EOTUtfDIFOLIA. 23 



* 



II., IV., and V. were fed Aug. 8 ; I., III., and VI. Aug. 9. 



The feeding was carried out as follows : — Boast meat was cut 

 into thin slices across the grain, and the fibre teazed and cut 

 into fragmer *. so minute that fifteen weighed, when damp, only 2 

 centigrams : each is therefore 1*3 milligram, or -^ grain ; and 

 sometimes smaller pieces were used. These small pieces of meat 

 were, on the fed side of the plates, placed on every leaf which had 

 secretion on the glands. I found it best to place two or three 

 of the smallest pieces each on a separate tentacle. On several oc- 

 casions I attempted to increase the size of the morsels, but was 

 forced to return to the smaller size on finding the meat covered 

 with mould instead of being digested. "When such mouldy leaves 

 were noticed, they were usually removed, lest the meat should 

 be washed off and putrefy among the roots of the plants, thus 

 vitiating the experiments. In the tedious process of feeding a 

 number of plants I occasionally dropped a morsel of meat among 

 the moss ; the infinitesimal error arising from these accidents 

 would be counteracted by the frequent renewal of the water in 

 the plates. 



The first difference noticed between the fed and starved halves 

 of the plates was on July 17th, when the fed side, viewed as a 

 whole, was clearly greener than the starved half. The difference 

 was quite distinct in all six plates, as both my father and myself 

 observed. The tentacles on the starved side were also of a redder 

 colour than those of the fed plants. 



The increase in the amount of chlorophyll in the fed plants thus 

 indicated is an interesting fact ; and it agrees with the result 

 of the final comparison of dry weights, which proves that a 

 much greater quantity of cellulose is manufactured by the fed 

 than by the starved plants. An increase of chlorophyll is asso- 

 ciated with an increased assimilation of carbonic acid ; and this 

 permits the production of a larger quantity of cellulose. An 

 average leaf from the fed and from the starved side were exa- 

 mined on July 18th *, when the difference was most marked, the 

 fed leaves being clearly distinguishable outwardly by their 

 dark purple hue, and microscopically by large and numerous 

 chlorophyll grains crowded with starch. 



Unfortunately no more leaves were examined at this date. 



The chlorophyll was removed by alcohol, and the sections then treated with 

 dilute acetic acid, washed, treated with iodine solution, washed again, and 

 mounted in glycerine. 



