320 



SCIENCE 



[N. S. Vol. XLIV. No. 1131 



tive indicators of vitality. It therefore seems 

 highly probable that the theory here presented 

 may be applied in those eases where other cri- 

 teria of antagonism (such as motion, growth 

 and length of life) are employed. 



It will be seen that action in a saturated 

 surface is the essence of this explanation. It 

 is evident that so long as this essential fea- 

 ture is preserved it makes little difference 

 what theory of antagonism we adopt. If the 

 antagonistic substances act in a saturated 

 surface antagonism must be governed by 

 Weber's law. 



Summary. — The fact that Weber's law gov- 

 erns antagonism is explained by a dynamical 

 theory formulated by the writer. 



This theory assumes that injury and death 

 result from processes which are inhibited by 

 salt compounds formed by the union of salts 

 with the protoplasm. If these compounds are 

 formed in a surface the amounts will (above 

 a certain limit) be independent of variations 

 in concentration and will depend only on the 

 proportions of the antagonistic salts. From 

 this it results that Weber's law must govern 

 the phenomena of antagonism. 



No matter what theory of antagonism we 

 adopt, it is evident that if the antagonistic sub- 

 stances act in a saturated surface antagonism 

 must be governed by Weber's law. 



w. j". v. osterhout 

 Laboratory op Plant Physiology, 

 Harvard University 



DO FUNGI LIVE AND PRODUCE MYCELIUM IN 

 THE SOIL? 



The recent investigations on soil micro- 

 organisms have revealed the fact that fungi are 

 found in soils in very large numbers some- 

 times reaching as high as 1,000,000 per gram 

 of soil. These numbers are found by diluting 

 the soil and then plating out only a small por- 

 tion of a gram. The colonies developing on 

 the plates represent the spores or pieces of 

 mycelium found in the soil. But this does not 

 tell us about the actual active life of the fungi 

 in the soil. However large the numbers that 

 are found, it remains to investigate whether 

 those organisms existed in the soil only in 



the form of spores, which were brought in by 

 some outside agency, or are a result of active 

 life in the soil in the form of mycelium which 

 may or may not result in the formation of 

 spores in the soil. The question is not how 

 many numbers and types of fungi can be 

 found in the soil, but what organisms lead an 

 active life in the soil. To what depth are these 

 organisms found to produce mycelium in the 

 soil ? And finally, do all or at least most of the 

 organisms isolated from the soil actually pro- 

 duce mycelium in the soil? 



At the suggestion of Dr. Charles Thorn, of 

 the Bureau of Chemistry in Washington, a 

 direct isolation of fungi producing mycelium 

 in the soil was attempted. Soil samples taken 

 at different depths, under absolutely sterile 

 conditions, were brought into the laboratory; 

 lumps of soil, about 1 em. in diameter, were 

 transferred with sterile forceps into sterile 

 plates containing cooled sterile Czapek's solu- 

 tion agar. The lump was placed carefully in 

 the center of the dish, which was immediately 

 covered and allowed to incubate for 24 hours 

 at 20-22° C. After this period mycelium was 

 found to radiate out of the lump of soil into 

 the medium. This mycelium was now trans- 

 ferred with a sterile platinum loop to sterile 

 slants of Czapek's agar, care being taken to 

 select the tips of the hyphse so as not to bring 

 the loop in too close contact with the soil. The 

 agar slants containing the transferred portions 

 of mycelium were allowed to incubate till the 

 organisms had developed well and were ready 

 for study. The organisms thus isolated were 

 not always pure. They had to be often sepa- 

 rated from one another ; this was accomplished 

 by establishing pedigree cultures of the organ- 

 isms. 1 



The organisms thus isolated are believed to 

 come from the mycelium that is actually found 

 in the soil. The period allowed for the incuba- 

 tion of the soil in the petri dish was not long 

 enough for spores in the soil to germinate and 

 produce such a mass of mycelium ; this is espe- 



i The methods of isolation and establishment of 

 pedigree cultures, as well as the details of the 

 work, formulas for media used and identification 

 of organisms will be published later. 



