266 Proceedings of Royal Society of Edinburgh. [sess. 
(1) That there are a larger number of micro-organisms in the 
summer than either in the spring or winter. They appear to reach r 
their maximum number during the month of August. 
(2) The number of micro-organisms found in the atmosphere 
decreases the higher one ascends. Hence near the Lincoln Cathedral 
there are fewer micro-organisms in the atmosphere (on any given 
day) than in the valley of the Witham ( Table (a) ). The same re- 
mark also applies to the number of micro-organisms found in the 
atmosphere on the top of the Trocadero Palace, Paris, where there 
are fewer than in a low-lying, but crowded, thoroughfare like the 
Boulevard St Germain. 
(3) There are a larger number of micro-organisms in the atmo- 
sphere of crowded centres than in less densely populated centres ; 
hence more in cities than in the country. 
(4) The number of micro-organisms are fewer when the air is 
“ at rest ” than at any other time. For instance, there were fewer 
micro-organisms in the atmosphere of tranquil places, like the 
cemeteries of Pere la Chaise, Montparnasse, and Montmartre, than in 
busy streets like the Kue de Rennes, Boulevard Voltaire, &c. 
During my researches, attempts have been made to isolate 
pathogenic microbes from the atmosphere, but up to the present 
without success. 
VII. Hypodermic Injections of Salicylic Acid for Phthisis. 
R. Wood, M.D., L.R.C.P. (mentioned in Part II. of this paper) 
reports that he has cured a girl of phthisis by injecting a saturated 
solution of salicylic acid into her system. He says, in a letter dated 
September 2, 1888 : — 11 1 have been injecting salicylic acid twice a 
week on a girl for one year , and she is now better” 
Dr Wood is injecting salicylic acid into the blood of another 
phthisical patient. On September 4, 1888, he sent me a bottle 
labelled — 11 Sputum of a girl , Webb, phthisical night sweats , age 14. 
Has spit blood. I am injecting a saturated solution of salicylic acid 
daily. — R. Wood.” 
I found in the sputum a considerable number of tubercle-bacilli. 
There is little doubt that salicylic acid (natural) is a powerful 
germicidal agent. 
In Part II. of this paper I gave the details of certain injection 
