64 RESPIRATION 



In the reduced form two molecules of glutathione give up the hy- 

 drogen of the sulphhvdrvl groups thus: 



COOH COOH 



CHXH 2 CHXH 2 



CH 2 CH 2 



CH 2 COOH CH 2 



CO— XH— C— H + H— C— XH— CO 



CH 2 — S— |H HI— S— CH 2 



Glutathione (reduced) 



These observations indicate that the presence or absence of free 

 oxygen conditions the respiratorv svstems in even the same species. 



RESPIROMETRY 



In recent vears use has been made of respirometers of a type 

 called the Warburg apparatus and of its several modifications, 

 which are especially adapted for use with germinating seeds, bits 

 of tissue of special organs, blood cells, and bacteria. To date, 

 however, all too little use of such apparatus has been made in the 

 study of respiration in fungi. 



One such study, indicating the usefulness of this procedure, was 

 made by Wolf and Shoup (1943). They employed a Fenn 

 respirometer to test the ability of species of the water mold, Al- 

 lomvces, to utilize certain carbohvdrates and organic nitrogen 

 compounds. After a period of starvation to remove the reserve 

 foods the several species were given various compounds singly 

 with the following results: 



