51 



time the butter-maker has had no means of controlling the species in his 

 cream, but has had to use those furnishad him by the farmer. The 

 bacteriologist can isolate and obtain in pure cultures the species of bac- 

 teria which produce the best flavoured butter. He can then furnish 

 them to the creameries to use as starters in cream ripening. 



Bacillus No. 41. 



Among the food products exhibited at the World's Fair in Chicago, 

 was a can of so-called preserved milk from Uruguay, which on 

 testing was found to have been inadequately sterilised so that it 

 was somewhat decomposed. Mr. W. M. Esten, of Middletown, was 

 at the Fair in charge of an exhibit of the bacteria of milk, prepared by 

 Prof. Conn and shown as part of the Experiment Station exhibit of the 

 U.S. Department ot Agriculture. The milk was placed in Mr. Esten's 

 hands for bacteriological examination. He isolated several species of 

 bacteria and took them to Middletown, where they were further inves- 

 tigate! by Prof. Conn, who was then engaged in the study of a consid- 

 erable number of species, found by him in specimens of milk obtained 

 in and near Middletown. The tests of the Uruguay species were begun 

 in the autumn of 1893. In December of that year it was found that 

 one of the species, which had been designated for convenience during 

 the process of the investigation as No. 41, produced such an effect 

 in the ripening of cream that the butter from the cream was pronounced 

 by experts as having the flavour of the best June butter. It is an in- 

 teresting circumstance that this bacillus, which has proved of so great 

 practical value, should have come from a specimen of milk from the other 

 side of the world, and that the accident by which the milk had been im- 

 properly prepared for preservation should have resulted in so useful a 

 discovery. 



The investigations by Prof. Conn have been carried on at Wesieyan 

 University in the biological laboratory, of which he has charge. 



II. By Prof. H. W. Conn. 



Experiments in Ripening Cream with Bacillus No. 41. 



The organism, while forming an acid in its growth in milk, is not 

 to be regarded as one of the milk-souring organisms. Milk under its 

 influence becomes acid, but the acid production is quite slight and the 

 milk, under no condition, becomes curdled. Even when growing at a 

 warm temperature the milk remains limpid for weeks finally becoming 

 somewhat brownish. After cultivation of the organism for a year or 

 more in the laboratory, its acid producing powers seem to be somewhat 

 greater than at first. 



This organism has proved the best of all of the many species of 

 bacteria thus far studied in its effect upon cream in ripening. 



