54 
Francis P. Kiernan, one of our own employees, who has been 
interested in the eenetics of Four-o’clocks for many years. A 
paper embodying the results of some of his studies recently ap- 
peared in The Journal of Heredity for October, 1926. 
Another new feature of the “ Ecological Section” is a bridge 
over the brook, just below the brook’s exit from.the swamp. This 
opens up a new and beautiful vista through the trees to those in- 
terested (Plate 00). 
The section is situated in one of the most beautiful parts of the 
Garden, and as I have stated in previous reports, it falls far short 
of what it might be, because of a lack of expert gardening as- 
sistance. 
For over three years, I have been interested in an aquarium 
culture apparently involving largely the alga, Chlorela vulgaris 
This is a very minute green plant which is used frequently 
in physiological research. It multiplies enormously in an ordinary 
round glass battery jar under the usual light and temperature con- 
ditions of a dwelling or office. Generally my cultures have been 
kept in a north window, although for some months they did 
equally well or better in a west window. The culture under our 
conditions is practically non-odorous, and when kept in the proper 
dilution gives the appearance of a beautiful translucent rich green 
solution. During this period, four medium-sized gold fish have 
been domiciled in this culture jar, which is 12 inches high and 734 
inches in diameter, and of about two gallons capacity. The water 
has been changed only by replacing that which evaporated, and once 
in six months or a year, the culture has been thinned, and the bot- 
tom and sides of the jar cleaned. During this period four ten 
cent cans of “ Rainbow” or similar fish food have been used. 
The fish have remained apparently in perfect health. This note 
is presented at this time in the belief that these observations might 
be of practical value to those interested in household and other 
aquariums. It seems to me that an aquarium prepared in this 
manner would be more ornamental and of far less trouble than 
those in common use. The golden red fish against a velvety, 
rich emerald green is very striking, and the plant culture, when 
kept properly diluted, only serves to conceal the fish for part of 
the time. Professor Tracy Elliot Hazen, of Barnard College, 
determined the alga for me. 
