192 STATE HORTICULTURAL SOCIETY. 



that a dead branch on a tree makes ahnost as great a strain on the main plant 

 for moisture as does a living one. It is one of the most important discoveries 

 of modern botanical science to the practical horticulturist, as by this knowledge 

 he can save many a valuable tree. When one has been transplanted some 

 roots get injured, and the supply of moisture in the best cases is more or less 

 deficient. Any dead branch, or any weak one, should therefore be at once cut 

 away. 



TEEES IN CITIES. 



An interesting paper has been recently read by Dr. Phene at Edinburgh on 

 the benefits to be derived from planting trees in cities. Among the beneficial 

 results to be attained are. he stated, the relief to the optic nerve through the 

 eye resting on objects of a green color. Just that which is effected by the use 

 of green or blue glasses in strengthening and sustaining the power of sight is 

 attained, or, at any rate, much aided, by the presence of green in nature ; and 

 in streets the only method to procure this result is by planting trees. It was 

 pointed out by the author that wherever opportunity exists nature provides 

 green and blue (the latter being the same color minus the presence of yellow), 

 and that as the absence of color produces snow blindness, and in tropical 

 calms, where the ocean presents only a white reflected light from a uniform 

 glassy surface, reduced optical power soon follows a long continuance of the 

 absence of bine color, which becomes immediately apparent on motion of the 

 waves. 



So in the streets to occupants of houses having a northern aspect, the glare 

 of the reflected light is injurious; but the efEectwould be much modified by the 

 coolness to the eye produced by the green of trees. In ancient surgery, j^ersons 

 having weak or declining sight were advised to look at the emerald. In the 

 old style of building, the streets being narrow were both cooler from the sun 

 not being able to penetrate them with direct rays, and less subject to noxious 

 exhalations from the scouring and purifying effects of the searching air to whicli 

 the narrow streets were subject, so tliat while there was no space for trees 

 there was also less necessity. Wide streets, on the contrary, are hotter, and 

 require tlie shade of trees to cool them ; and, as in the case of London, which 

 had so far done without trees in its streets, it was pointed out that not only are 

 modern streets compulsorily wide, but that the enormous increase in metro- 

 politan buildings renders every sanitary question one of importance ; and the 

 chemical property of trees as shown by experiment gives them an important 

 standing, irrespective of ornament or the pleasure they produce. Some of Dr. 

 Phone's experiments on this subject have extended over a period of thirty 

 years, and he it was who first tried the planting of trees in the streets of 

 London. Since the reading of a former paper by him at Manchester, wherein 

 the importance of the subject was pointed out, a number of streets in wealthy 

 localities have been planted, and even Trafalgar Square, in the heart of the 

 metropolis. 



