124 
Microbiology. — “Mutation in Penicillium glaucum and Aspergillus 
niger under the action of known factors.” By H. J. WATERMAN. 
(Communicated by Prof. M. W. BeIJERINCK). 
(Communicated in the meeting of May 25, 1912). 
A. Penicillium glaucum. 
In solutions of p- and m-oxybenzoie acid a spontaneous growth 
of mould had developed at the air. From this material, which 
floated on the liquid, a pure culture of Penicillium glaucum was 
obtained by isolation on malt agar, which culture was used in the 
biochemical investigations described by Prof. BörsrKEN and WATERMAN.) 
It looked quite normally green and had the peculiar “mould smell”. 
The culture was transferred some times in the course of a year; 
mostly to protocatechetic acid, and a few times also to p-oxybenzoic 
acid as sole carbon food. : 
After about a year, white, jelly-like spots were observed in a great 
number of the films floating in ERLENMEIJER-flasks of 200 ce. Seen 
under the microscope these spots proved to have produced but few 
spores, whereas the mycelium and hyphae were normally developed. 
The phenomenon became still more prominent if considerable quan- 
tities of other substances retarding the growth, such as salicylic and 
trichloraerylie acid were added to the p-oxybenzoic acid. 
TABLE I. 
50 cc. tapwater, 0,05 °/. NH4CI, 0,05 °/o KH,PO4, 0,02 °/, MgSO4; ¢ = 20 —21°: 
Nr | Carbon compound added. 13 days after inoculation 
| J | 0,15 gr. p-oxybenzoic acid (0,3 ®/o) Aspect rather normal, only slightly 
2 | ” ” ” ” mucous. 
| 3 | 0,15 gr. p-oxybenzoic acid + 3,5 Very mucous, most in 5, least in 
mgr 
salicylic 
acid 
ENA : EE 3, In 4 and especially in 5 few 
‚5 ra op 5 » +122 spores. 
6 | 0,15 gr. p-oxybenzoic acid + 3,4 Ee 6, 7, 8 successively like 3, 4 and 
| -68 
Ny Een » ie, DE © 5, but the phenomenon less 
| oS 
Ee » » +4] S3 | marked. 2) 
1) BoëseKEN ‘and Waterman. These Proceedings Vol. 14, p. 604, 608, 928, 1112. 
2) Salicylic acid retards the growth more than trichloracrylic acid. 
