54 JOURNAL OF THE [April, 



recalled an experience just a year before. Wishing to obtain 

 some ragweed pollen for the microscope, I was disappointed in 

 finding the material scarcer, and a change in the form or condi- 

 tion of the pollen-grains. They were less spherical and less 

 spinous. In a word, less like a tiny chestnut-bur. This may 

 be noticed in my figures in the Article, " The Pathology of Pol- 

 len in Hay-Fever," my only specimens to draw from being a few 

 late, or October pollens. 



Conclusion. — Let us epitomize these differences in our 

 home-catch, and that in the mountains. 



1. The place of observation in both instances was along a 

 much-travelled road, yet the air at home contained more and 

 slightly coarser mineral matter. 



2. The general vegetable debris, composed of fibres, the dust 

 of exuviation, such as plant-cells, scales etc., was in greater 

 quantity at home. But, then, this is the center of a busy agri- 

 cultural industry. 



3. In the New Jersey " catch " the vegetable debris contained 

 in the air, both in kind and quantity, exceeds very greatly that 

 of my retreat in the mountains. The interesting fact, too is the 

 marked presence of fungus-spores in the home-atmosphere. 



4. We have next the fact of the great quantity of pollen in 

 the air at home. Also this notable fact that the great prepon- 

 derance of pollen is that of the Ragweed. This plant also gives 

 off a large amount of dust, which we may suppose to be like the 

 pollen, acrid and toxic. I think we may admit that this plant 

 deserves its bad reputation as the worst foe of the hay-fever 

 subject. It is the irritant preeminent. 



5. The fact is significant, that the greater catches for quantity 

 and quality occur in August and September. The pollen-grains 

 of October are fewer, and functionally feebler. The spines 

 then on the ragweed-pollen are almost abortive. 



The summer air of the White Mountains is less heated than 

 at home. I should think the daily average difference would be 

 fully ten degrees. It is also much drier, hence delightfully 

 bracing. I know nothing of any scientific experimentation on 

 the chemistry of the air of these regions, but I think it cannot 

 be otherwise than that it receives a terebinthine effect from the 

 balsams, which clothe the mountains. Hence, from the three 

 factors here mentioned, the air should be markedly tonic. If 



