CHAPTER X. 



PROFESSOR ARTHUR ON PLANT RESPIRATION— SURFACE VIEW 

 OF EPIDERMAL CELLS OF A CARNATION LEAF— SEC- 

 TIONAL CUTS THROUGH A CARNATION STOMA— 

 PHYSIOLOGICAL DEMANDS OF CARNATIONS 

 FOR FRESH AIR. 



DEFICIENT ventilation has been, and still is one of the 

 great errors in the successful cultivation of carnations. 

 If there is one thing the anatomical organs and a knowl- 

 edge of their functions teach, it is an unlimited amount of fresh 

 air, a comparatively dr\^ atmosphere for the foliage, and a mod- 

 erate suppl}^ of moisture for their roots. This is the implication 

 of the plant's structure. Its physiology, and forty years of costly 

 experimental processes have proven these postulates true. Some 

 species of plants rely exclusively for their support on elements 

 drawn from the atmosphere. The ancestral forms of Dianthus 

 life were, and are, habitats of high, dry and cool latitudes. If he- 

 redity is a factor in vegetable life, the foliage of their progeny 

 must love air and their roots have an aversion to an excess of 

 water. 



They are most florescent and healthy in the fall and spring 

 months, when the ventilators are open, and fresh air is freest. 

 Cool air is not necessarily pure air, but it is commonly accepted 

 as an equivalent for ventilation Ventilators should be raised in 

 carnation houses and fire started when the mercury falls below 

 forty degrees outside. 



I am pleased to accept Professor Arthur's views on the anat- 

 omy and respiratory functions of carnation plants, but entirely dis- 

 sent from his conclusion that their nature warrants a system of 

 sub- watering as being in harmony with any known law governing 

 this plant's nature. 



