238 Plants in Sleeping -liooins. Are they Zfn?iealt?iy. 



Plants in Slesping-Hooms. Are they Unliealtliy? 



THIS long agitated question is now definitely set at rest by the experiments of 

 Prof. K. C. Kedsie, of the Michigan Agricultural College, and are tlms related 

 in a letter of his to Governor Holt : 



Not to leave this matter in the condition of mere conjecture, I have gathered and 

 analyzed specimens of air from a room where the influence of growing plants would 

 be exhibited in a greatly exaggei'ated form. Thus, instead of taking the air from a 

 room containing a few plants, I gathered it from the college greenhouse, where more 

 than 6,000 plants are growing. I gathered the air before sunrise on the mornings of 

 April 16th and 17th ; the room had been closed for more than twelve hours, and if 

 the plants exhaled carbonic acid to an injurious extent, the analysis of air from such 

 a room would certainly disclose this fact. The three specimens of air gathered on 

 the morning of April 16th from difi"erent parts of the room, gave 4.11, 4.00 parts of 

 carbonic acid in 10,000 of air, or an average of 4.03 in 10,000. The two specimens 

 of air gathered April 17th, gave 3.80 and 3.80 parts of carbonic acid in 10,000, or 

 an average on the whole of 3.94 parts of carbonic acid in 10,000 of air, while the 

 out-door air contains 4 parts in 10,000. It will thus be seen that the air in the 

 greenhouse was better than " pure country air." This deficiency of carbonic acid 

 was doubtless due to the absorption of carbonic acid and consequent accumulation of 

 oxygen during daylight, since the windows of the greenhouse were closed day and 

 night on account of the cool weather. 



To ascertain whether the air of the greenhouse had more carbonic acid by night 

 than by day, I gathered two specimens of air in different parts of the house, at 

 2 o'clock P. M., April 17th. These gave 1.40 and 1.38 parts of carbonic acid in 

 10,000, or an average of 1.39 parts, showing that the night air contained more car- 

 bonic acid than did the air of day. 



Now, if a room in which were more than 6,000 plants, while containing more car- 

 bonic acid by night than by day, contains less carbonic acid than any sleeping-room 

 on the continent, we may safely conclude that one or two dozen plants in a room will 

 not exhale enough carbonic acid by night to injure the sleepers. 



It is so easy to be deceived by a name ! I lately saw an article showing the bene- 

 ficial and curative influence of flowers in the sick room. Instances were related 

 where persons were cured by the sight and smell of flowers, and without question 

 their influence is good. Yet flowers exhale this same carbonic acid by day and by 

 night! The flowers, by their agreeable odor and delicate perfume, impart an air of 

 cheerfulness to the sick chamber which will assist in the recovery from lingeiing 

 disease, notwithstanding the small amount of carbonic acid which they constantly 

 exhale. 



The presence or absence of carbonic acid is not the only question in regard to the 

 healthfulness of plants in a room. The state of moisture in the air of the room may 

 become an important question, especially in the case of persons afflicted with rheu- 

 matic or pulmonary complaints. But I will not take up that subject. 



