184 BACTERIOLOGICAL CHEMISTRY 



against Staphylococcus and B. mycoides, being bacterio- 

 static at concentrations of about 1 in 100,000 and 

 bactericidal at 1 in 8000. 



A. flavipes, when grown on tryptone medium or 

 corn-steep liquor medium, gives an alkaline bacteriostatic 

 filtrate active at dilutions of 1 in 320 to 1 in 1300 against 

 Str. pyogenes, pneumococci, and CI. welchii, very slightly 

 active at 1 in 5 to 1 in 10 against staphylococci and 

 inactive towards Str. fcecalis, E. coli and Aerobacter 

 cerogenes. It can be obtained as a gummy precipitate by 

 concentration of the medium in vacuo and addition of 

 ten volumes of acetone. 



Penicillium resticulosuni, grown on Czapek-Dox 

 medium, gives a metabolism solution which inhibits 

 the growth of Staph, aureus at dilutions of 1 in 320 to 

 1 in 2500. The antibacterial substance can be precipitated 

 from solution by the addition of acetone after concentra- 

 tion, the yield being about 1 g. per litre from a filtrate 

 inhibiting Staph, aureus at a dilution of 1 in 80. It is 

 readily soluble in water, contains 3-8 per cent, of 

 nitrogen, and causes complete inhibition at a concentra- 

 tion of 1 in 160,000. It is very sensitive to acid, being 

 destroyed by contact with 0-1 N hydrochloric acid at 

 room temperature. 



Of thirty-nine moulds which were tested seventeen, 

 all of the genus Penicillium, had antibacterial activity. 

 They could be divided into two groups ; I, active against 

 Staph, aureus, Str. viridans and C. diphtherice, were 

 contaminants of laboratory media, and II, which were 

 active against E. coli and Eberthella typhosa in addition 

 to the above organisms, were mainly fi-uit contaminants. 



Among a large number of species of Fungi imperfecti, 

 Wilkins and Harris showed that about 40 per cent, of 

 Aspergillus species and 25 per cent, of Penicilliuyn 

 species gave substances antagonistic to one or more of 

 the test bacteria, E. coli, Staph, aureus and Ps. ceruginosa. 

 Very few representatives of other genera were active, the 



