50 JOURNAL OF THE [April, 



persons suffering with this malady. From the i6th of August 

 until the 20th of September, each day when not prevented by 

 rain, three ordinary slides charged with glycerine were set out 

 of doors to catch the foreign contents of the air. Meanwhile, 

 my son under instructions, made similar exposures at our home 

 in Freehold, N. J., whose elevation above mean tide is about 

 200 feet, and that of Maplewood about 1,500 feet. 



While in the White Mountains the catch of each day was 

 studied in the night with the microscope, and notes were duly 

 taken. After my return home, September 21st., the daily ex- 

 posure of slides was kept up until the 22d of October, when, 

 having for several days failed to catch any pollen, it was dis- 

 continued. After having studied the home-slides, I restudied 

 those from the mountains, and finally a patient comparison was 

 made through a number of evenings of both series, the two em- 

 bracing nearly one hundred slides, of which forty-five were 

 taken at Maplewood. I had hoped to double this number, but 

 the frequent rainy days prevented. 



In respect to the two places chosen for observation : — at the 

 home-station the malady exists in the kind and extent so general 

 in the Eastern States, while my mountain-post, with a wide 

 region around, was highly favored as a sanitarium from this 

 ailment. But we must not look for entire exemption, even in 

 the very best of these resorts, unless Nature has been left to her 

 virgin forms and moods. All are somewhat affected, and some 

 even seriously, by the local industries, whether of agriculture, 

 or other industrial pursuits. For those afflicted with the severe 

 forms of this disease, complete immunity is not possible where 

 the air is charged with the mineral debris and vegetable efflu- 

 vium, which elsewhere prove irritants to the respiratory passages 

 of persons who are pathologically susceptible. Even in these, 

 the most highly favored places of the White Mountains, at the 

 time of the flowering of the grasses, and cutting of hay, which 

 is usually over when the summer guests have come, there are 

 sporadic cases of Hay-Fever among the natives. These seem 

 to be of the type known as June, or Rose Cold. The main irri- 

 tant is the dust and pollen of the Timothy, or Herd's-Grass, 

 Phleum pratetise, and probably in a less degree of the wild 

 Perd's-Grass, P. alpimcm. 



When the south winds prevail there is invariably an increase 



