104 on A SUBSTANCE KNOWN AS ' AUSTRALIAN CAOUTCHOUC." 
been named, is confined to a depressed portion of the district, the bottom: 
of which is sandy and grass-covered ; it occurs on the banks forming the 
margins of the depression and also on the sides of island-like elevations 
which are scattered about it 
tanical interest of this curious substance begins with the opinion 
given with respect to it by the Rev. M. J. Berkeley. “I think, X m | 
collemal in an riens &tato. $^ thin slice Pam direi of rm i 
but I see nothing like fructification. I have met with no collemal atal | 
like it before.” Mr. Whittell, in a letter in the ‘ Adelaide Observer _ 
. (Sept. 30, ae gives some further account of its microscopic appear- — 
ances :—“ If one of the thin layers be held up to a strong light, there — 
will be seen in «ibi substance a number of blnckslooking streaks. Ifa 
generally (though not in every case) that the binik streak is in reality a 
hollow space lined with dark brown sporules (?), with a lighter coloured : 
335sth of an inch in " diamete ter, but some are as large as the s5go — 
iden mycelium appeared tobe formed by the union of ‘small cells ge E 
Several iatoms, oo to the genera Cocconema, and Navicula 
se also detected in the matrix of the substance by Mr. Whittell. 
Another writer in the ‘ Register’ (May 8th, 1866) describes thin sec- 
tions as “ exhibiting under the microscope, especially if moistened witha 
solution of caustic potash or benzole, a granular and cellular structure 
with entangled fibres resembling the fibres of decayed fungi.” Mi 
also m 
uu structure. Mr. Archer 
Club, to whom I submitted a fragment for. examination, gives, B 4 | 
think, the true explanation of this s appearance. He writes to mé, E 
recent letter, to the following effect :—*“ I think the substance in qu&* — 
tion is certainly or ganic,—some kind of gum with accidental things im- — 
ed, such as bits of Bh unge dees some co ufervoid or fan threads, 
a 
E 
[2 
Tu 
i] 
S 
e 
e- 
D 
“t 
o 
F 
F 
= 
= 
— 
- 
E 
Q 
$ 
z 
=. 
& 
state, is evident from the miscellaneous collection 0! 
ue reique which — mieroscopists have detected in bcd 
vires a sufficient proof that their presence 18 
: The s suggestion which occurred to Mr. orari that it is the 3 
ib 
One can esie 
= pee Ay m Ea p. 174. 
