BOTANICAL GAZTETE. 83 



watered, and so situated as to receive the sun (preferably the morning 

 sun) for at least several hours, raise the i)roportion of aqueous vapor 

 to about the health standard 



This formula may serve as a guide in the use of plants for hy- 

 gienic purposes ; but under conditions of actual disease it will be 

 necessary to increase the proportion of plants according to the degree 

 of humidity sought, or as the indications of individual cases may de- 

 mand. 



It should be stated that, to obtain the best results, both the 

 rooms occupied during the day and the sleeping apartment should 

 contain plants. It was for a long time the opinion of scientific inter- 

 preters generally that plants in sleeping apartments were unwholesome 

 because of their giving off carbonic acid gas at night ; but it has been 

 shown by experiment that it would require twenty thrifty plants to 

 produce an amount of the gas equivalent to that exhaled by one baby- 

 sleeper: so this is no valid objection to tlieir admission, and not to be 

 compared with the benefit arising from their presence. 



We have no desire to underrate other means of treatment while 

 upholding the nnportance of our subject. Exercise in the open air is 

 of immense advantage in phthisis, and during the warm season the 

 consumptive should be moving among his garden plants, and, if he 

 be a lover of flowers, should assume personal charge of them. Again, 

 no one will dispute the value of certain tropical climates for judicious- 

 ly selected cases of phthisis ; but the practice of indiscriminately send- 

 ing patients to them is certainly to he deprecated. 



New health-resorts (many of them copiparable only to the patent 

 nostrums) are constantly being pressed upon the public, but too often 

 a trial of them brings only disappointment, and the consumptive is 

 rendered more miserable by the annoyance of travel and the anxiety 

 of being separated from all the endearing relations of home. And 

 even where travel is desirable, it is. for financial or other reasons, 

 quite imjjossibie in a large proportion of cases. 



To have always at hand and readily available so complete and 

 withal so agreeable a health-resort at home as that furnished by a 

 room well stocked with plants must prove an inestimable boom to the 

 despairing invalid. 



The Origin and Survival ok ifiF. Typks of Flowers. — In a 

 lecture delivered before the California Academy of Sciences, October, 

 1879, Prof. Cope proposed the hypothesis that "the consciousness of 

 plant-using animals, as insects, has played a most important part in 

 modifying the structure of the organs of fructification in the vegetable 

 kingdom. Certain it is that insects have been effective agents in the 

 preservation of certain forms of ])lants." Dr Hermann Mueller has 

 recently published a book in which he seeks to explain the existing 

 variations in the forms of flowers on the principle of selection. He 

 supposes that insects of different tastes bred peculiar flowers, just as 

 men breed peculiar races of cattle. Carrion loving insects bred their 

 kind of flowers, and long-tongued insects, the tubular kinds, and 



