CERTAIN SPECIES OF MUcoR 255 
mum growth is given irrespective of time. Furthermore, in any 
consideration of the numbers in the tables, it must be borne in 
mind that these numbers are liable to be misleading when inter- 
preted from a standpoint of medium exclusively, because they 
include the inherent tendency of the species. To be specific, 
Mucor griseosporus has been found by the writer to be more 
plastic than other species; for example, it varies from 8 mm. to 
20 mm. in height according to the medium used, while Mucor 
spinescens is always a low-growing form, heights varying only 
from 2 mm. to 8 mm. having been obtained. 
TABLE II 
HEIGHT AND GROWTH OF MUCORS WITH MISCELLANEOUS GELATIN MEDIA 
| tue cor | Mucor | Mucor 5 nag Mucor | Mucor | Mucer | Mucor Mucor | “Sah 
Media big No.5 | No.4} No. No. 7 | No. 40 No. 16 | No, 12 vie 
‘ . 2] . pap} . re J] 
E sds gel s[elslais als ae fade 
Levulose. ./35| IV|15) III 15 III 15| III |rs| III r5 III 15| III | x0 If i's Ir|8 lI 
Dextrine. .|35} IV|15)| III 15) III 15| [II jr5| I1I}r5\ IIL |r5 III | -8| II 5] 11/8/I 
Glucose (a) 25) IV |17 III |16 III) 15) IE |r4) 111 15 III |12 II |rol 1 9| I1\3 
Glucose. . .|30| IV|12) III IT III| 10} III }x3| I1L}1r2| III jroj III} 4) IL | 7| 11/6 
Dung ext. |20| IV|17| III |20) III|12) III |20| III) 8} IL! 5! If| og IL |5| IL|s 
Raulin (a) |30| [V|x1| III |xz| III|15| III] 5) I1)18) III} 8} I | §| II | 9| III |3 
Maltose ../20| IV|12| III |zz| II| 9| TIL| 4) I11L|xr1| IIL |roj IIT} 6) Il | 5 lis 
actose | Iv|ro 11 |r5| 111 | x9] 111 8| III} s| II} 4) Il} 3) Its I|3 
Beef broth |36| II|12| IL |r4| Il|11z| IL} 9| IL! 7} IL} 9| Ij} of ILi8 is 
nulin....|/z0| III| 8) I r3| II| 8| II|xo| II] 5} IL} 8| I} 7 11|3| 11/3 
Sucrose. . .|— oa rr III) 5) If|ro I) 9 IL) 5) I) 5) I \5| I )2 
ri ce a Fag 9} II} 5} II} 8} II} 5} If| 4 ee Pig iealie 
Chec —| —|—} —| of I} si It] 7) Wt) 5) rl} —| aittig! Ils) 1 
In the early experiments gelatin was used as the culture 
medium, but later this was replaced by agar, as the latter was 
found to serve the purpose equally well and, moreover, there is 
less possibility of its liquefaction. The following were the for- 
mulae used as given in abbreviated form in the first column of 
TABLE II: levulose, dextrin, glucose, maltose, lactose, inulin, and 
sucrose, in each case 2 per cent. of the carbohydrate with 12 per 
cent. gelatin; glucose (a), 5 per cent. glucose, gelatin 15 per cent. and 
one drop of 10 per cent. lactic acid; dung extract, fresh horse dung . 
extracted with cold water and 15 per cent. gelatin; Raulin (a), 
Lendner’s (1908) formula with substitution of glucose for sucrose; 
beef broth, 0.75 gm. Armour’s beef extract, 50 gm. gelatin and 
500 c.c. water; inorganic salts, 1.0 gm. KNO;, 0.5 gm. KH2PQ,, 
