24 FORESTS, WOODS, AND TREES 
pulmonary diseases of the pine plantations, which are so 
extensive in and around this famous health resort (Fig. 
2). In his book on Yhe 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- 
