44 Proceedings of Indiana Academy of Science 



growing in northern regions, ripen as a rule in a shorter time and 

 here the question of illumination or other causative factors requires 

 further study. 



Many deciduous plants continue to cast off leaves and form nev/ 

 ones even when removed from temperate zones to the tropics. Oaks and 

 beeches never cease to do this, while others such as the cherry gradually 

 become evergreen in Ceylon but cease to bear flowers. The peach, on 

 the other hand, produces flowers and fruit during the entire year 

 (1, Bd. II, p. 271). Experiments of this kind are much to be desired 

 in temperate climates where artificial conditions could be supplied. It 

 is difficult or impossible to cause many plants to bloom out of season 

 while others lend themselves more or less to the process of forcing. 

 However, artificial forcing causes abnormal development in some plants, 

 as in the case of Lily of the Valley which is caused to develop the flowers 

 before the leaves (7, p. 238). 



A good many questions are concerned in the solution of certain 

 points connected with periodicity. The experiments of Johannsen (34) 

 show that treatment with ether or chloroform for 12 to 24 hours will 

 cause the buds of such plants as Synvga vulgaris and Prunus triloba to 

 open three to six weeks earlier than the plants not so treated and the 

 activity of various functions was increased. Elfing and Lauren had 

 observed before this that ether or chloroform increased respiration if 

 the doses were not too strong, although this has been questioned. 

 Molisch (35) has shown that if certain plants are immersed in water at 

 30° to 35° C, for 10 to 12 hours the resting period may ba terminated. 

 For example, a hazel branch one side of which was subjected to warm 

 water bloomed in nine days while the other side which was untreated 

 was still in the resting condition. Forsythia suspensa bloomed in 12 

 days after such treatment while the control was still unopen. Syringa 

 bloomed 40 days after the waim bath while the control was still dor- 

 mant. The responses shown in these experiments leaves certain ques- 

 tions unanswered. 



Fitting's experiments (36) with Erodiiim gruinum and E. ciconiuvi 

 are interesting in this connection. He found that when, on a cool 

 morning, deep blue flowers of these species were put in a box having a 

 temperature of 40° to 42° there occurred quickly a sudden change of 

 color. Within three seconds the blue flowers changed to a light rose 

 and a few minutes later to a bright red. When returned to a cool place 

 the blue color soon returned. Furthermore, the reaction of the cell 

 sap is often indicated by the color of various living cells. Thus, the 

 red color of rose petals and beet-roots shows that the cell sap is acid 

 while the blue color of the hyacinth, blue bell, or cranberry shows that 

 the sap is neutral or slightly alkaline (1, Bd. I, p. 490). We also have 

 striking color changes caused by oxidases. Among these is the brown 

 color assumed by the exposed flesh of apples, the prussian blue shown 

 by Boletus when broken and the dark color of raw rubber (37, p. 390). 

 The oxidation of the sap of Rhus to a black lacquer varnish in air by 

 laccase is akso well known. 



Other properties of the enzymes are noteworthy. The dried sub- 



