KLE.MKXTS OK TilK IKON GHUl'K 47 



ASCOLI (1.), wlio .MU-reL'<]eil in ;i.->cerUiiuili{» the iinpoi-tiilit fact 

 that the plasmic acid (|^ 252) isohiteil from the* lutrKMu of wtist 

 contiins about i per cent, of (uuisketl) iron, whicli is |)rol>aljly 

 attfiched direct to tin* |»ho.s|)hoiu.> .itoiu. Attempts have iih-eadv 

 been made to utilise this fact in pliarinacy and me<licine ; and 

 tiiuce 1900 there has been recovered from ycw^t ^rown on a 

 lii-rhly ferru;^'inous nutrient medium, a llN>ion pnxluct of nucleiii, 

 to wliich the name ferratogea has l)een ^'iven, .md which contjiins 

 alxjut I per cent, of iron in or^'anic c(anbination and readily 

 absorbed in the intestines. According to G. Maki'Mann (II.), 

 the iron in fungi (and especially in I'eiiirilliuvi) is usually in the 

 ferrous state, and oidy exceptitnially present in a higher stiige 

 of oxidation ; this has been deinon.stiiited by treatment with 

 hydrochloric .solutions of potjissium ferro- and ferri-cyanide. 

 Au exception is itlVorded — at least according to \\. KfssEuuw 

 (II.) — by yeast (pres.sed yeast in jiarticular), the staltilitv of 

 which is .saifl tt) be inJluenced by its abundant content of ferric 

 phosphate. In addition to its part as an indispensjible foodstutf, 

 iron also .seems to act as a .stimulant : according to the indica- 

 tions alVorded by compai-.itive experiments undertaken bv 11. M. 

 KiCU.VUDS (I.). 



Tlie nu»t;ils allied to iron, namely nickel, cobalt, and man- 

 ganese, have Iteen tested on Asjwri/i//u.-< ni</'.r h\ MoLlsen (11.) 

 with regard to their capability of rephicing the first-named, but 

 were found unsuitable. This does not, however, imply that the 

 fungi entirely reject the.se elements. On the contrary, it has 

 been shown by W. 1'kkkfki{ (Il.)and 11. M. Hkiiauds (1.) in 

 cultures of AspenfiUiiK uit/er and P'tiiri/liuiii ijlmiruin, that cobalt 

 and nickel, in the condition of sulphates, can exert a similai- 

 stimulative action to that already a.scribed to zinc (>5 J 29). The 

 optimum ipiantity of the .sidt of the tir.st-name<l met;il was found 

 to be 0.002 percent., which gave a crop almo.st double that from 

 the check experiment without cobalt In the case of nickel 

 sulphate the correspomling (piantity is 0.03^ per i-ent. (con.se- 

 quently much greater), and this increases the crop two and a 

 half to three fold. 



As long ago as 18S4, manganese was detected by J. Schloss- 

 BEKCiEit and O. DcEPri.Nii (I.) in various nuishrooms — e.ij. Ai/aru-u^i 

 ih'licinKtiif, At/, arrensis, and A mam tit iiiiiaran'a — and sub.-wpientlv 

 by lilssixcKu (I.) and others in Lart'iriiia j>ij>t'i<itu.<. HotJi 

 physically and chemit-ally this element .seems to plav a very 

 noteworthy part. From what has alreiidy been stjiteii in fi 215 

 of Vol. i.. the reader is aware th.it many fungi cont;iin oxidising 

 enzymes allied to the laccase in the .sjip of the lac tree. Now, 

 in the ash of the latter, (Jabuiel Hektuand (1 II.) has di-scovennl 

 up to 2.5 j>er cent, of manganese. Subseipu-nt experiment,s 

 have led this worker to conclude — though this h.is not vet been 

 contirmed — th.»t nianiranoe is the real active aijent in the 



