256 PovaH: A CRITICAL STUDY OF 
0.25 gm. MgSQ,, 0.5 gm. CaCl, 100 gm. water, and 12.0 gm. 
gelatin; check, 12 per cent. gelatin with distilled water. 
In this experiment the cultures were made in test tubes and 
about 5 c.c. of the medium were used. Thecultures were kept in 
the dark at room temperature (15-22 degrees C.). All cultures 
were made in duplicate, and in many cases, where there was a 
doubt in the mind of the writer, the experiment was repeated. 
The results are best obtained by consulting TABLE II, from which 
we see that levulose is the best medium in this series, followed by 
dextrin, glucose (acid), glucose, dung extract, Raulin’s (acid) in 
the order named. Sucrose is the poorest, probably because many 
of the forms are unable to invert it. 
TABLE III 
HEIGHT AND GROWTH OF MUCORS WITH MISCELLANEOUS AGAR MEDIA 
Mucor | Mucor\| Mucor | Mucor | Mucor| Mucor | Mucor 
Medi No. 26 | No. 34| No.5 | No. 24 | No. 28} No.6 | No. 51 
edia | 
BO jm) ol slo [alo ial o iz] o jal 
Rolled cates i ss ae 70| IV |68| IV}42| IV |30} IV |4o; IV}45| IV j10| IV 
(tusuaapatsen: NGAI eis 50| IV |27| IV|30| IV |18) IV }23; IVj24} IV |r0| IV 
Potato agatis sce See, eee 65] III |55| I1V|37| IV |32| IV j21| III} 22} III |ro} If] 
CORR Meal ps0 e ee, a 5| IV '60; 111|35} III |20| 11 |30) III|25| 111} 5| 11] 
ROOM Sa Oso Sie Ses Veoh es 40} IIT |60} III} 10} TIT |25| III |25) 111) 15) ILI |ro} 171 
Rpg abe ioe oie eRe Re ere, 50) IV |40) III} 25| III |20| III }20) III|}20| III} 8} 1 
Glucose-nitrate agar........... 40| III} 8} I11}27) IV |13) IIL |17| II} 19) III |13} I 
Mannit-a fates pect ..+.- 125! IL] 9} IIT|22/1I1 \15| III |x) 111} 6| IL |roj Il 
Wheat-starch paste........... 50| III |}25) IL}25|III|20| III \20 20) III |ro; I 
Grapes. 2 rs Sis ee 2z| IL} 3) Il}1o| Il \rs} I1}z8} BHjzo} IL} 5) 1 
Rovy ee bar. ys oe 38| II] 5 r4| II 10) 9p TEs TEE or I 
; 27) ib i3gic Utiast 3) ja0} Fie or 4 Sr Ti see 
Sucrose-nitrate agar. aOR Eh Ae a 40) TE ad Tixe Reg 9 eae BN, | 
nnit-nitrate agar.......... 20 25) 1) 8} Firat yt leet oer I 
riven Eng tres bala ante an 40 rol Tp sli Sf oR Fo VE set 
1a or: Bara eg egret ate eee I Ij Ijro} II} r 1; Ii—| I} gz I 
In the next series of experiments various agar and complex 
media were used. See Taste III. An explanation of the 
formulae of these media follows. Potato agar was made according 
to the method given by Thom (1905), and apple agar was pre- 
pared in the same way. For bean agar Thom’s (1910) formula 
was used. For glucose-, mannit-, and sucrose- asparagin agar, and 
for glucose-, mannit-, and sucrose-nitrate agar, a combination of 
mineral salts (0.25 gm. MgSO,, and 0.5 gm. KH,PO,) was 
used with 5.0 gm. of the carbohydrate, and 2 1.0 gm. of either 
