24 FORESTS, WOODS, AND TKEES 



pulmonary diseases of the pine plantations, which are so 

 extensive in and around this famous health resort (Fig. 

 2). In his book on The Medical Aspect of Bournemouth, 

 published in 1886, he devotes a chapter to this subject. 

 He recognised the useful effect of trees as the best form of 

 shelter from wind, being much superior to walls, banks, 

 and rocks for that purpose, owing to the absence of the 

 back wind which ricochets from these obstructions, and is 

 often more destructive than the direct wind. Moreover, 

 trees admit free circulation of air. He considered, however, 

 that the main hygienic value of pines was due to the 

 emanations from their leaves, which caused the atmosphere 

 of a pine forest to have decided antiseptic and disinfectant 

 properties. 



Dr. A. D. Edwards, Medical Officer of Health, Bourne- 

 mouth, thinks that emanations from the pine trees largely 

 planted there " have a cleansing effect on the atmosphere, 

 and also have a sedative effect on the respiratory mucous 

 membrane. It is doubtful whether the emanations have 

 any effect on the actual germs, as the proportion of turpen- 

 tine in the atmosphere would be too small to have any 

 effect." 



I have been unable to find any statistics to show the 

 incidence of tuberculosis in pine districts ; and such statistics 

 would be valueless, as there are so many other factors in- 

 volved, such as ventilation and size of the bedrooms used 

 by the inhabitants in such districts. 



It is needless to enter into a defence of the beneficial 

 effects of the shelter afforded by forests and plantations. 

 In the country, whatever may be the case in large towns, 

 the stagnation of the air so ardently combated by Prof. 

 Leonard Hill does not exist, except in low-lying and often 

 badly drained depressions, where no one would locate a 

 sanatorium. There is no fear of stagnation of air in the 

 British Isles, even if the proper share of forests was 

 established. The question, however, remains, what are the 

 emanations of pine forests, and what effect have they, if 

 any, on phthisis ? A statement that " the balsamic emana- 



