K.— BOTANY 215 



mycelium submerged under increasing air pressures in commercial 

 glucose solution to which calcium carbonate had been added, yielded 

 from 80 to 87 per cent, gluconic acid based on the sugar originally present, 

 in eight days from the inoculation with spores. They have recently patented 

 the process with the specification that the air contains substantial amounts 

 of oxygen and agitation is effected by blowing it through the cultures. 

 The same patent covers the preparation of koji acid by Aspergillus 

 flavus. 



Gluconic acid was formerly characterised by objectionable features in 

 its production and by high costs. It is now finding a commercial outlet 

 because calcium gluconate is preferred to calcium lactate as a means of 

 administering calcium to children. It can be injected into tissues 

 without causing necrosis, and its injection into cows suffering from milk 

 fever has given remarkable results ; it has unusual effects in increasing 

 the egg shells of hens suffering from calcium deficiency. It has recently 

 been incorporated in tooth pastes. 



There are many other acids formed by moulds. Wehmer in 1918 

 patented a process for the production of fumiric acid. The fungus 

 employed was named Aspergillus fumaricus, but no proper diagnosis 

 was given. Thom regards it as being very close to A. niger : according 

 to a statement by Wehmer the fungus ten years later had lost its property 

 of forming the acid. 



H. Raistrick and his collaborators working in this country have added 

 a great deal to our knowledge of the metabolic products of moulds. 

 From their continued investigations it seems to be becoming increasingly 

 evident that compounds of almost every type known to organic chemistry 

 can be synthesised. They have succeeded in obtaining sixty compounds 

 never previously prepared in an organic chemist's laboratory. It is 

 suggested by P. W. Clutterbuck that ' it is possible that a particular 

 organism builds up its own particular polysaccharide and from it, by a series 

 of reductions, oxidations, condensations and hydrolyses, synthesises from 

 it its own characteristic metabolism products.' An interesting point 

 arising from their investigations is the production of anthroquinone 

 pigments by some species of Helminthosporium. It is well known in 

 the technology of dye-stuffs that such a-hydroxyanthroquinones give rise 

 to excellent dye-stuffs, but are difficult to manufacture economically. 

 Since the yield is good and sugar is cheap the possibility has arisen of em- 

 ploying these organisms for the manufacture of a-hydroxyanthroquinone. 

 Another point which shows what practical results may be expected from such 

 research is that penicillin, a metabolism product of Penicillium notatum, 

 is non-irritant and non-toxic, but has a strong though differential anti- 

 bacterial power. Further, it was found that several species of Fusarium 

 form large quantities of alcohol from glucose and it is suggested that this 

 might be turned to account technically in the production of alcohol from 

 waste vegetable matter. 



The romantic discovery of vitamin D led to the finding of ergosterol 

 in yeasts. A vast amount of research has since been carried out, both 

 with yeasts and with moulds to find the most suitable method of pro- 

 duction of ergosterol, which when irradiated gives the antirrachitic 



