296 



THE AMERICAN MUSEUM JOURNAL 



nition of museum authorities. Animals 

 of all sorts can be studied and identified 

 at the American Museum and at the 



•^ 



m^ 



Four (-olonies of livitiK ba<-l('ria. Each contains mil- 

 lions of individuals and has growii from an invisible in 

 oculalion of the nutrient jelly. In order, from the 

 toj), they are: the pink water ha<:illns, a lypical-lofjk- 

 ing colony, so-called because of the pink pigment it 

 pro<luces when grown on agar jelly; the nitrogen-Cxinf; 

 bacterium, which grows in the soil and assimilates at- 

 mospheric nitrogen to serve as food for higher plants; 

 the ray fungus, which produces a cattle disease to 

 which man is also subject; the yellow coccus, a mi- 

 crobe common in the air, which produces a yellow 

 color when grown in a culture medium 



park of the New York Zoological Society, 

 higher plants at the New York Botanical 

 Gardens. The discoverer of a new mi- 

 crobe however, has been forced to de- 

 pend for identification upon comparison 

 with written descriptions unless he could 

 obtain what he wanted from the Krai 

 collection at Vienna, which has never 

 l)een Ijrought back into a complete con- 

 dition since Dr. Krai died several years 

 ago. The need for a permanent stand- 

 ard collection of l)acterial types has been 

 urgently felt l)y all workers in this 

 country; and for the last five years this 

 need has Ijeen met by the museum of 

 living l)acteria, maintained by the de- 

 partment of pulilic health of the 

 American Museum. 



Bacteria cannot be dried and put away 

 in trays like bird skins. They are iden- 

 tified, less by their simple structure than 

 by their physiological behavior, by the 

 ferments they produce and the changes 

 set up in the media in which they grow. 

 This collection must be a museum of 

 Ii\ing specimens and the task involved 

 in bacterial horticulture is no small one. 

 ^lost bacteria grow on a jelly made up 

 with meat, peptone, and the extract from 

 a Japanese seaweed, agar. Some how- 

 ever, require very special foods, as vari- 

 ously and exactly compounded as those 

 that are prepared in the diet kitchen of a 

 hospital. Some must have egg; some, 

 blood; some, milk; some, salts of special 

 kinds. Some need air while others must 

 l)e cultivated in tubes from which oxygen 

 has been remo\ed l)y special chemical 

 means. Some will live for weeks with- 

 out attention, while others must be 

 transferred to a fresh tube of food jelly 

 every three days. A laboratory helper 

 is busy all the time preparing the culture 

 media for these small but exacting plants, 

 while the bacteriologist in charge is quite 

 fully occupied in transferring them at the 

 proper time, an<l to the proper medium. 



