466 



NATURE 



[August 15, 191 1 



obvious loss of health, and, to judge from the 

 work of Graham Lusk, his "efficiency" in the 

 technical sense will not be affected. Work 

 actually done will apparently be done at the same 

 cost in Calories. We have, however, no certain 

 knowledge as to how far that reduction can go 

 (if it can occur at all) without affecting his ulti- 

 mate capacity for work. 



The review of modern experimental investiga- 

 tions with which the report opens well repays 

 perusal as coming from authors highly qualified 

 to appraise it from an independent point of view. 



In connection with the experimental measure- 

 ment of Calorie requirements, they do well to 

 emphasise the point which Dr. Leonard Hill has 

 recently made so clear — namely, that estima- 

 tions made upon a man in a calorimeter at uni- 

 form temperature and in still air must not be 

 applied in practice without proper qualifications. 

 Vary the conditions, lower the external tempera- 

 ture, and especially increase the movement of air 

 to which a resting man is exposed, and the 

 demand goes up. It may be enormously increased. 



Our knowledge concerning the energy require- 

 ment for the performance of external work is 

 fully and very ably reviewed and appraised. It is 

 shown that such data as those obtained by Bene- 

 dict and Cathcart enable us to state with fair 

 accuracy the increase in the demand for energy 

 which goes with a given increase in work. This, 

 however, applies only to work done within com- 

 paratively narrow limits. We have, for instance, 

 no satisfactory data bearing on the cosjt of the 

 more sedentary occupations. 



In discussing the protein question the authors 

 seem to be less at home. They do wrong, for 

 example (though the point is perhaps of no great 

 importance), in associating our modern conception 

 of the metabolism of protein, involving, as it does, 

 irhportant chemical, as well as energetic, con- 

 siderations, with the name of Rubner, who has 

 given attention only to the all-important details 

 of protein nutrition under compulsion born of 

 other people's work. The authors justly pillory 

 in the course' of their historical discussion the 

 vice of quotation at second hand ; but it is just 

 as bad to over-emphasise quotation from one par- 

 ticular original source unless its authority out- 

 weighs all others. On the protein question much 

 more illuminating work and discussion have come 

 from America and this country than from 

 Germany. 



The work embodied in this important document 

 was carried out under the supervision of the Food 

 Investigation Committee appointed by the 

 Ministry of Munitions. 



THE AFFORESTATION QUESTION IN 

 BRITAIN. 

 TN a previous article the present and future 

 -*- positions of the timber supplies of this country 

 were considered. The afforestation question will 

 now be briefly dealt with. Lord Selborne, in the 

 House of Lords, recently asked whether the 

 NO. 2546, VOL. lOl] 



Government was in a position to announce its 

 decision on the report of the Forestry Sub-Com- 

 mittee of the Reconstruction Committee, mention- 

 ing the pressing necessity for replanting which 

 existed throughout the country. Lord Peel re- 

 plied that the Government had accepted the report 

 of the Forestry Sub-Committee, and that a central 

 authority for the United Kingdom would be set up 

 and planting be proceeded with with the least pos- 

 sible delay. This announcement will be greeted 

 with approbation by all acquainted with the urgent 

 importance of the afforestation problem. Differ- 

 ences of opinion on administrative questions exist, 

 but these are trivial compared with the main object 

 in view — the afforestation of the waste lands of 

 the country. Forestry in its general aspects is 

 a branch of economic industry of which the 

 British public has known very little in the 

 past. It is not surprising that it should have 

 remained in ignorance of its importance. For we 

 have no forests in Britain in the sense in which 

 the word is understood in Europe and elsewhere 

 in the world. Ours are pretty woodlands. In the 

 future it will be necessary to grow commercial 

 woods, for the war has demonstrated immis- 

 takably that, as a mere- matter of safety in the 

 case of emergency, we must have a reserve supply 

 of timber and pit wood in the country. 



It has been already shown that we have to face 

 the probability of all our commercially exploitable 

 woodlands being cut out either during the war or 

 in the years immediately following the peace. In 

 1914 we had 3,000,000 acres of woods in Britain. 

 On a rough estimate half of these will disappear, 

 and the areas occupied by them be replanted. This 

 work is more a matter for the proprietors, who 

 have received a high price for material which in 

 many cases was almost unsaleable before the war. 

 In some instances Government assistance may 

 prove necessary. These fellings will not be all 

 to the bad, since considerable areas, commercially 

 worthless in pre-war days, owing to the poor 

 methods on which they were grown, will have 

 been cut out. 



But these ij million acres do not affect the 

 main afforestation problem before the nation. • 

 Since the outbreak of war, Ministers and others 

 have been wisely preaching thrift and con- 

 servation of the national resources. There are 

 some i6f million acres of mountain and heath 

 land in Great Britain, much of it bringing in a 

 very small return per acre, from 2S. 6d. down 

 to a few pence. 



Some of this land is above the limit in eleva- 

 tion of tree growth; other parts may prove re- 

 clai'mable for agriculture. Land which is utilisable 

 for the production of food should not be afforested. 

 But there remains, so far as an estimate can be 

 formed, at least some 3,000,000 to 5,000,000 

 acres which can be made to produce, in the 

 national interests, a higher return both in'money 

 and general utility when placed under tree crops. 

 Moreover, on these large areas of waste land — 

 for, in the sense that they are not being put to 

 j their best use in the interests of the community. 



