1899] TREES IN WINTER 401 



thinks, be attributed to the respiratory combustion exerted by the 

 woody and liberian tissues from the moment when the leaves have 

 lost their assimilatory activity up till the beginning of the winter rest. 

 " As long," he says, " as a certain degree of moisture remains in the 

 tissues, life is maintained there, and it may occur that the starch 

 reserve is entirely absorbed. In the same way, after the fall of the 

 leaf, woody plants still continue for a certain time to vegetate and to 

 respire ; it is in the liber that this function seems to be most active 

 and most persistent. It is not only a more or less complete absorption 

 of the starch reserve that is produced in autumn, it even works a 

 profound change in the distribution — due to this that the foci of attrac- 

 tion are displaced. It is known, in fact, that starch is borne always 

 to the points where vitality is most developed. Now in this season 

 the only regions where there still remains a residue of vegetative 

 activity are, on the one hand, the buds which the young branches 

 bear, on the other the roots whose vegetation is prolonged for a certain 

 time after that of the aerial organs exposed to the first cold. In pro- 

 portion as the season advances the respiratory combustion slackens, 

 and from the moment when the vegetable enters into the period of 

 latent life, the distribution of the starch remains stationary during 

 nearly three months" {Comptcs Bendics, vol. cxii. for 1891, p. 964). 



I think it would be difficult to quote or translate a passage which 

 reflects more faithfully and lucidly the inevitable results of true 

 scientific observation and experiment upon the veritable scientific 

 intelligence. The facts are interpreted aright and referred back, so to 

 speak, to their real, i.e. their physiological cause. It has been main- 

 tained that the winter period of rest of our deciduous trees is not 

 dependent on external conditions, such as temperature or moisture, but 

 on internal changes, and especially on such as enable the starch- 

 containing cells to transform their starch into sugar. Sachs thought 

 that possibly there must be a very slow production of ferments before 

 the buds can develop in spring, as they cannot by any means be caused 

 to develop in autumn or beginning of winter, although meanwhile their 

 reserve materials are not chemically changed. Nevertheless, a study 

 of the actual condition of affairs within the veil of mystery that 

 enwraps the winter forest, reveals the groundlessness of the opinion 

 that the reserve materials are chemically unchanged. In point of 

 fact, we discern that the protoplasm contained in the delicate, colour- 

 less tissues of the bark becomes very rich in fatty matter, probably 

 operative as a resistant to the extremes of cold. The starch, moreover, 

 which in most of our trees is laid up in the wood and in special reser- 

 voirs below the buds, is during the hard season very rich in substance 

 and poor in water, the grains seem to be smaller than in summer, and 

 amylodextrine seems to accompany it, i.e. altogether it is hardly in a 

 condition well fitted for chemical transformation. No doubt glucose 

 or other combustible carbohydrate may gradually all the while be 



