Fungous Flora of the Soil 435 



1-1,000) was used for pouring ten plates. In other cases further dilution 

 (1-10,000) was made before pouring the plates. Prior to pouring some 

 of the plates, a few drops of potassium hydroxid (KOH) were added to 

 the melted medium in the test tubes to make it alkaline. 



As a check on the isolations F, G, and H, isolation I was made.' The 

 roots of a pepper and a corn plant left over in the soil from 19 10 were care- 

 fully removed from the soil and taken immediately to the laboratory, 

 where the soil was washed from them. Roots from each plant were 

 immersed in mercuric chlorid solution (1-1,000), where they were kept 

 for two minutes. Following this, they were transferred to sterile water. 

 Parts of these roots showing discolored areas were transferred with a 

 sterilized scalpel to plates containing agar. The results, in general, were 

 what was expected, that is, the same saprophytes that were isolated from 

 the soil were isolated from the roots. (For details note results of isolations 

 F, G, H, and I.) 



Isolations J, K, L, M, and N were made after the same method, which 

 is as follows : From the flasks containing the inoculated water, about i cc. 

 of the solution was poured into a petri dish. Into a second and a third 

 dish a few drops of sterile water were poured. By means of a platinum 

 loop, dilutions from plate I were made by transferring a few loopfuls of 

 the inoculated water to the sterile water in plates II and III. To the plates 

 was now added the melted agar cooled to about 40° C. (tested by apply- 

 ing the test tube to the skin just below the eye). 



From the soil sample designated O the fungi grew out and fruited on 

 the cheesecloth, as previously mentioned. To isolate these organisms 

 and obtain pvire cultures, dilution plates were poured. 



Results of isolations 



Other forms than those here indicated appeared in the petri dishes. Many 

 forms never fruited; others were lost in pouring dilution plates for pure 

 cultures where some of the rapidly growing fungi crowded out those grow- 

 ing more slowly. A number of apparently different Fusaria were encoun- 

 tered, but classification was not attempted. Three of these Fusaria were 

 used in one series of inoculations of potato tubers; two gave positive 

 results, while one was negative. Time has not permitted further con- 

 firmation of these results, so it cannot be stated positively that Fusarium 

 oxysporum Schlecht. was isolated from the soil by cultural methods, 

 although the morphology of the Fusaria isolated does not differ materially 

 from the dry rot organism of the potato. 

 Forms isolated from the different samples. — 



A. July 14, 19 10. Chaetomium olivaceum Cooke & Ellis, Fusaria, 

 Mucor circinelloides van Tiegh., Mucor hiemalis Wehm., Mycogone nigra 



