re;views 303 



influence on crop distribution, while topography, both in its influence 

 on local climate and its bearing on cultural methods, has a prominent 

 influence, and general climate, again, influences the distribution in a 

 rather broad way. To avoid confusion with an earlier statement, let us 

 repeat that productive capacity, as influenced by soil and climate, while 

 making the land profitable or unprofitable, does not so directly influence 

 the character of the crop as do factors affecting cost of production. 



The first part of this paper, as has been stated, is a general discus- 

 sion of ecological principles, and while presenting an interesting out- 

 line, we are frank to say that it gives the whole paper a top-heavy 

 appearance, occupying nearly half of the whole space. As the subject 

 is not particularly new, we trust that a frank criticism may be as much 

 in place as a full review. The discussion is for the most part orthodox, 

 yet contains many good passages which should be credited to the 

 author. On page 14, for example, we read : '*A habitat then does not 

 so much consist in rocks or hills or lake, as it does in so much moisture, 

 so many degrees of heat, such an amount and quality of light. A 

 habitat is not viewed dynamically until it is placed on a strictly factorial 

 basis. The field worker sees plants growing in sand along the sea- 

 shore. He must think of them in terms of the water balance of the 

 plant, the abundance of light, temperature, and so forth." 



We quote this passage as an admonition. Too often the ecologist, 

 even after careful instrumental records are secured, thinks only as he 

 sees things superficially. In this connection we wish to refer to a pas- 

 sage in the description of the ordinary succession in a habitat begin- 

 ning with rocks and culminating with a deep humified soil. In the 

 later stages of this succession, we read on page 32 : "By the time a 

 heath stage has been reached the cliff is usually well covered. This 

 stage is succeeded by a shrub stage and often by a coniferous stage. 

 Gradually oaks come in, increasing the shade and lowering the water 

 loss from the soil as well as the oxidation rate of humus. The oaks are 

 succeeded in time by more mesophytic trees— beech and maple, which 

 are again the culmination of the successions. In all of this series the 

 action of the plants has been toward an increase in soil .and moisture 

 until the conditions became suitable for plants like beech and maple." 



It is not, perhaps, technically correct for a reviewer to inject too 

 much of his personal opinion, especially if he has not space to present 

 his arguments in full. We can not, however, subscribe to the idea con- 

 veyed by co-joining the two words above which we have placed in 



