I 



6 



usually rich in the albuminoids. The proteids are the basis of 

 protoplasm, and protoplasm is the substance which is inva- 

 riably present in every living cell. As protoplasm is the 

 complex compound in which life always manifests itself, the 

 importance of the albuminoids out of which protoplasm is 

 made, becomes self-evident. 



Doctor Vines, in his new work,* in treating of the repose 

 of the above compounds, says : *' When once deposited the 

 reserve materials undergo no change, or, at most, the proteids 

 may slowly undergo some alteration, so long as the organ in 

 which they are deposited remains in an inactive condition. 

 An organ in this state is practically dead for the time being, 

 all its metabolic processes being arrested. It is capable, more- 

 over, of resisting injurious influences, such as extremes of 

 temperature and desiccation, which would prove fatal to it, 

 were it actively living. It is obviously in consequence of this 

 property possessed by such organs during what we may term 

 this state of suspended animation, that vegetation is main- 

 tained in regions in which the cold of winter is severe, and in 

 arid tropical regions. The time of the possible duration of 

 this state, without permanent loss of vitality, varies very 

 widely." It is well known, for example, that some seeds retain 

 vitality for a long time, especially starchy ones. With the 



quickening influences of warmth and moisture supplied by 

 spring-time, the reserve materials undergo changes which con- 



vert tliem into substances that can readily travel to seats of 

 vital activity w^hen they arc employed in growth. 



Starch. — Returning to the carbohydrates, they will be 

 taken up in the order of their importance. The test for 

 the detection of starch is the very satisfactory one of iodine 

 solution; which turns this substance blue, while it fails to pro- 

 duce the same color in other cell contents. My means of this 

 reagent, starch is found quite generally at a short distance 

 below the growing point, and usually in the form of compound 

 granules, the component parts of w^hich separate quite easily. 

 These masses, or compound granules, vary greatly in size, and 

 the smaller particles of starch do not exhibit this compound 

 nature. Starch-bearing cells of well-matured twigs may con- 



* tt 



rixysiolo^^y of Plants," i8S6, p. 172. 



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