290 BOTANICAL GAZETTE [OCTOBER 
It is seen from this table that the amount of nitrogen gain in 
this case is well within the limit of error. The slightly higher 
value in the earlier work is believed to be due to less skilful use 
of the analytical methods. In harmony with this idea is the fact 
that Myceliophthora was the first one of the set which was analyzed. 
The results on the duplicate were thrown out altogether as worth- 




TABLE VII 
Dry wt N of N of Total Nof; N _ 
No. Fungus —" — oe pe = Pen 
a 6 c d mg. 
Ee hey ee less lcd ca ee 0.63 0,63 1: cee 
BB Ey re 7 eee °.70 0.70 |eveeeeeee 
Py CANE Ge cB aks eal ae ne os 0.66 0.66 4.5055 pee 
14 | Myceliophthora......... 2.8 0.07 0.70 0.77 0.11 
15 | Hormodendron........: Cee 0.14 0.56 0.70 0.04 








less, due to a bad frothing in the distillation which evidently 
carried over some of the alkali. This difficulty was relieved by 
exchanging the soocc. distillation flasks for the 1000 cc. size, 
and using only stick zinc instead of granulated, after which no 
further difficulty of this kind was experienced. These results 
therefore give no foundation for nitrogen-fixation in these fungi, 
under the conditions of the investigation. 
INVESTIGATION III 
This investigation proceeded to work further with these same 
fungi, omitting Acrostalagmus, in nitrogen-free media, according 
to the method employed by TERNETz (19), PENNINGTON (25); and 
others, using an apparatus for aerating the cultures by air drawn 
through strong potassium hydroxide and concentrated sulphuric 
acid. The apparatus is shown just as it was used in fig. 18. It 
consisted of six 500 cc. Erlenmeyer flasks connected up in sets 
of three in such a way that the air to each set passed over the follow- 
Ing series: a U-tube of pumice, saturated with strong NaOH; 
a U-tube containing strong H,SO,; a wash bottle } filled with 
Sterilized, distilled water; a tube 2 cm. in diameter containing 4 
