222 BACTERIA. 
TABLE NO, 4. 
Showing the Relation of Film Colors to Atomic Weights according 
to Mendelejeff’s Periodic Law. 
4th Period. 6th Period. 9th Period. 
Cu [63 White. Ag|108| Bright yellow. |Au|199) =§ ———— 
Zn |65 White. Cd |112! White. Hg 200|Scarlet & yellow. 
Gaj6s) = —— [In ]113) —-— (T1204; 9 ———_ 
el ee ———_ Sn |118|Brownish yellow|Pb 207/Chrome yellow. 
As /|75|)Reddish orange.|Sb 129, Orange red. |Bi |210|Chocolate brown 
Se |78/Reddish brown. |Te |125 Purplish Brown... aE 53 ——_—— 
Br |80 we T (127) Brown. i evel ister —_— 
FEBRUARY 23, 1887—FIFTY-THIRD REGULAR MEETING. 
William G. Stevenson, M.D., chairman, presiding ; 
forty-five members and guests present. 
The following paper was read : 
BACTERIA. 
BY MISS ISABEL MULFORD. 
Judging from the literature which has lately arisen 
upon this subject, one readily infers that it is one of 
great and increasing interest, not only to those who are 
practically engaged in microscopical research, but to 
those who are interested in the great problems of life 
and its environment,—to those who are striving to learn 
more of the wonderful phenomena attending life, and 
death, and decay. 
A few forms of bacteria were observed a long time 
ago. Leeuwenhoek in 1675, O. F. Miller in 1773, and 
Khrenberg in 1838, described several forms, and made 
some attempt at classification, but until quite recently 
the notions concerning these lowly organisms were ex- 
ceedingly vague and crude, and no attempt was made to 
control their action. ; 
Though the study of bacteria presupposes micro- 
scopical work, since the largest cells cannot be seen ex- 
cept by the aid of a good microscope, many forms are 
106 
