BUREAU OF CHEMISTRY. 367 



shucked oysters, as well as the nature of the spoilage, the numbers 

 and kinds of bacteria present in decomposing oysters, and the criteria 

 by which it is possible to determine whether oysters are fresh, stale, 

 or sour. The results of the investigation to date indicate that a test 

 for hydrogen-ion concentration of the 03'ster liquor may supplement 

 the organoleptic examination in determining the quality of shucked 

 oysters. It is also indicated that a determination of the total num- 

 bers of bacteria present in decomposing oysters is of no value in 

 judging the quality of oysters. 



In work on the classification of bacteria in food products, a new 

 method for separating the several sections or subgi-oups of the colon 

 group of bacteria has been found. This method has been applied 

 to a large series of cultures collected from soils and from fecal speci- 

 mens in order to determine its usefulness in differentiating the fecal 

 cultures from those of nonfecal origin. At present the application 

 of this method to the estimation of the sanitary quality of water 

 is being studied. Two papers giving the results of this work are now 

 in press. It is believed that the continuation of this work will 

 simplify and improve the methods used in the identification of pollu- 

 tion organisms in water supplies. 



Work on a comparative study of the floras of spoiled canned foods 

 was continued. Several cultures from food-poisoning outbreaks were 

 collected and studied. A rather large collection of type cultures of 

 Bacillus hotulmiis and of the para-typhoid-enteritidis group have 

 been kept in stock. 



A study of the biological factors in the deterioration of forage and 

 feeding stuffs is under way. The possible agency of pure cultures of 

 particular molds in animal disease is being tested in feeding ex- 

 periments. Later it is proposed to deal with mixed cultures. In this 

 way it may be possible to determine to what extent spoilage in feed- 

 ing stuffs becomes a source of loss of domestic animals. 



Cultural studies of Penicillium and Aspergillus and species of 

 related genera were continued. The large collection of mold cul- 

 tures maintained now includes about 900 numbers, representing 

 species and strains obtained from widely different sources. During 

 the year 238 cultures were furnished to correspondents for the identi- 

 fication and verification of molds. 



The many data accumulated during the cultural work under this 

 project, now in its twentieth year in the department, necessitated a 

 restudy of the basis for nomenclature in the groups Penicillium and 

 Aspergillus. This monogi'aphic undertaking has reached the form 

 of a preliminary manuscript, but it will require one or more years 

 for completion, since it is carried on in the intervals between other 

 work. 



During the year work was continued upon fermented foods — the 

 methods of their preparation and preservation and a study of the 

 organisms concerned in such fermentations. Fermentation of cu- 

 cumbers raised at the Arlington Experimental Farm was continued, 

 special attention being given to the relation which the quality of 

 the cucumbers bears to the resulting pickles. Additional studies 

 were made on the bacterial spoilage of pickles during fermentation. 

 Cabbage was also fermented and sauerkraut was canned experi- 

 mentally, on the basis of both a household and a commercial product. 



