60 THE MICROSCOPE. April 



SCIENCE-GOSSIP. 



Commercial Use of Red Pigment From Bacteria. — It is 



a well known fact that many bacteria produce beautiful pig- 

 ments. The Chinese have long used a pigment, " Aug- 

 Khak," for the coloring of foods. The microbe producing this 

 color grows readily on all starch-containing substances. The 

 rice is grounded and boiled and inoculated from an older cul. 

 ture. In about six days an abundance of the coloring matter 

 is produced. The organism only grows in the presence of air 

 and in a cool damp place. To check the growth of deleterious 

 species arsenic is added, which does not influence the pigment 

 form. 



Micro-Organisms on Coins. — The Revue (VHygiene pub- 

 lishes an interesting account of some experiments made at the 

 bacteriological laboratory of the Military Hospital of the Dey 

 at Algiers. Dr. H. Vincent explains that money is specially 

 liable to be contaminated by saliva, pus, pathological secretions, 

 dust, and the morbid germs that may be found in dirty pockets 

 or on dirty fingers. He does not think, however, that evidence 

 of this danger can be easily obtained by placing dirty coins in 

 culture broth. The investigations at the Dey Hospital were 

 conducted in a different manner. A piece of cotton- wool about 

 the size of a pea was dipped in water and sterilized. Pieces of 

 wool thus prepared were seized with pincers that had been held 

 in a tlame and were gently passed over the coin to be examined . 

 The pieces of wool were then placed in culture broths and kept 

 in a temperature of 35° C. The product, which soon contained 

 various micro-organisms, was sown anew in gelatine plaques so 

 as to isolate the bacteria. In other cases it was inoculated in 

 doses varying from one to five cubic centimeters, in the blood 

 or under the skin of rabbits, guinea-pigs and white rats. A 

 lengthy description of the methods employed and the results 

 obtained is given. The number of bacteria found on the sur- 

 face of coins varied very considerably, on silver and gold from 

 four hundred and sixty to thirty-five hundred, and on copper a 

 still larger number. To destroy many of the non-pathogenic 

 microbes some experiments were made at a temperature of 37'' 

 C. The injection of mixed cultures from coins only produced 



