Jri.v. 1004.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



143 



mistaken for any otiier less desirable, kind, and w Iumi tlio 

 first prejudice has been ovcrcomo, it will doubtless l^e 

 added to the list of t;ible delicacies. 



A peculiar funyus of a somewhat gelatinous consis- 

 tency and brownish-red colour, having; a resemblance in 

 shape a human e:ix, and popularly known as " Jews' 

 liars " (Hinicola aurlciihi-liidiia'), is not uncommon on 

 dead elder trees, and although not usually included 

 under edible species in this country, is perfectly safe to 

 eat, and a closely-allied species {H. polytriclia) is 

 esteemed as a luxury by the Chinese, by whom it is 

 cultivated on a large scale. When dried, the price of 

 this fungus rang-cs from .£30 to £50 per ton, the retail 

 price being about one shilling per pound. This fungus 

 occurs in abundance in \cw Zealand, where it is 

 collected for the Chine.se market, the annu.nl value of 

 the exports ranging between £15,000 and X-(o,ooo. 



These amounts are, howexer, entirely eclipsed bv tlu' 

 hundreds of millions of pounds sterling expended 



4. Fungi t^rowiog on insect.s; a, '-, Curdijcrpg mi/itartt ; '/, conidial; li 

 axiferous form of fruit; buth are growing on th.; chrysalis of 

 some inject; c,Cordtjeep% a>i:ularix, growing on a caterpillar. Nat. 

 size. 



annually on products depending entirely on the work 

 done by a lew closely allied and lowly organised species 

 of fungi known as \'easts {Sacc/iaromyccs). I'he pro- 

 ducts alluded to are fermented or alcoholic liquors ; 

 wines, Ix-crs, and b.ome-made ginger-beer alike owe the 

 amount of alcohol they contain to the activity of yeasts. 

 The yeasts are very partial to sugar as food ; in the 

 production of wine, the sug-ar is present in the juice from 



the crushed grapes ; in Ijreu ing lie<'r tin- starch pr<'s<'nt 

 iiii barley is converted into sugar during the preliminary 

 process of malting. In either case yeast is added to the 

 sugary extract, and wheni tlu- prop-cr leni|)eralnrc is 

 maintained, fermentation takes plarc. Such fermenta- 

 tion is the index of the \ital arti\il\- uf the \t'asl or 

 lungus present in. the solution. 



1,'nder such favourable condilions as regards tempera- 

 ture and food supply the yeast grows very r.apidlv, in- 

 creasing in numbers by a rapid vi'gvtative or non-sexual 

 method called budding-. During this acli\ity the sug:u- 

 is u.sed ;vs food, and the by-producls, or lli(',<-;e portions of 

 the sugar not utilised by the fungu.s, .-iri' gixcn off under 

 the form of carbonic-acid g:i,s and alcohol res[wi-li\cl\'. 

 The former is the cause of the bubbling or efferxescence 

 as it escapes intoi the air, the l;ilter remains in Ihe 

 lir|uid. 



In olden limes, the sweet wort or g?'ape juice was left 

 expO'Scd tOi the air, .and fermentation was effected by 

 yeast cells present in the air coining inito' (~onta,ct with 

 the liquid. .\t llie pi-esenl time llie \c,isl Is ridded to 

 the liquid, and in some breweries pure cultures of differ- 

 ent forms O'f yeast are used, depending on the (|u.ilily, 

 flavour, or keeping- power of the beer desired. 



V'east is quite as indispensable to llie I)al<er as to tin; 

 brewer. To the latter it has beeni shown that alcohol is 

 the by-product ol most value ; whereas to the baker, who 

 utilizes the yeast for the purpose of leax'eiiing bis dough, 

 the carbonic-acid gas is most im|)orlant. The fungus, 

 being thoroughly mixed with the <loug'hi containing- 

 sug-ar and water, coim-mences active growth, ;md flic 

 carboinic-acid gas liberated bubbles up tlirougli tlie 

 tenacious dough and converts it into' a liL;lit, s])oiigv 

 mass, 'lire alcohol formed is dis.sipated (luring the 

 process of baking-. 



\\'ith one important exception liirgi are not used 

 medicin:illv, unless the lanious t'liinoe rungiis is ad- 

 mitted. The oine included in tlie Hritish- l'li;irniacnp<ela 

 is Ergot (Claviceps pur piirea)^ the sclerolium of a fungus 

 parasitic on the ears of rye and numerous olher grasses, 

 .-mtl h;is ;i wide distribution. 



When flowers of rye, wheat, or p;isliire grasses are 

 infected by the spores of ergot floating in tlic air, the 

 part developing; into a grain under noi-ni:il i-on,ditions 

 bec-o^n-ies changed into^ a black, horn-sli.-iped hoflv .-ibout 

 half an incli in length, and coirposerl of a srlid iiia^s ■ 

 O'f mvc<.-liiim, termed a, sclerotium ; this is llu" l'^r!7(;L "i 

 part used medicinally. It cont.'iins a siib.sf.-inij^j^alird 

 lirgotine, which, although iJoisonous, is (>£^'real'',v;ilut;;< 

 as a medicine. ' -^ r\'>\'^ 



When the h'rgot is mature its surface is eo\erG^^with 

 myriads of very minute conidia, or summer-sporeSjjC 

 wliich are immersed in a somewhat yisod,'. sweet SM^V 

 stance that is \c.ry attractiye tO' fhe.^'Vn'irl Otheri' small 

 insects, who, in \isiting one grass floaver after another, 

 disperse the conidia, and thus elfect the distribution of 

 the fungus. When the grass <lies iiii the .•iiitumn the 

 Ergots fall to the gronnd, .and remain unrliangerl until 

 I'le following- spring;, when a new form of Iniil grows 

 frofin the sclerotium, the spores of wlii<'li infect the 

 gr;iss flo'Wers in the spring-. 



Xo'twithstanding- its medicinal value, b'rgol is said to. 

 cause serious diseases to human beings when, it is 

 ground up along- with grain toi form flour, and when 

 e;iten by horses or cattle it causes abortion. 



The Chinese fungus alluded to, and called " summer 

 p'rmt, winter worm " bv the Celestials {Cordyicp^ 

 sinensis), is interesting as being one of a small g-roup of 

 funL'i that develop on living- insects. .Some attack 

 moths, wasps, Ac, but the majority are met with on 



