22 



with granular contents. Went observed the same thing in Monascus 

 (Ann. des Sci. nat. Bot. 1895, No. 1), and the writer has also seen it in 

 that fungus. 



The cowpea fungus also stains various starchy substrata, but the 

 writer was never able to get as bright colors as with the melon fungus. 



The red color of the perithecia is insoluble or nearly so in ether, 

 chloroform, benzine, benzole, or carbon bisulphide. The color is very 

 slowly soluble in ethyl and methyl alcohol, but decidedly more so in 

 the wood alcohol than in the 95 per cent ethyl. That is, after 48 hours 

 there was no change in the ethyl alcohol, and even after several weeks 

 most of the perithecia were still bright red, although a few had faded; 

 after 48 hours in the methyl alcohol the red perithecia (from a potato 

 culture) were a little paler, and after several weeks a few only were 

 pale red, most of them being pure white. In a saturated solution of 

 chloral hydrat the color changed at once slightly, was dull orange-red 

 in 15 or 20 minutes, yellowish-red ia 2 hours, and dull yellow in 48 

 hours. In chlor-iodid of zinc the color soon changed to dark purplish 

 red and then to brown. The mycelium and interior of the perithecia 

 did not blue, but changed from white to yellow. In mineral acids 

 (nitric, sulphuric, hydrochloric, chromic), strong or weak (weakest 

 solution 1 per cent), the perithecia changed instantly from red to yel- 

 low and remained yellow. The same change took place in acetic acid, 

 but required several minutes when a 1 per cent solution was used. In 

 a saturated solution of ammonium carbonate the perithecia were purple 

 at the end of 48 hours, but there was no visible change during the first 

 2 hours. In strong ammonia water they changed immediately to pansy- 

 purple, and did not at once lose color, but were paler at the end of 48 

 hours. 



A purplish stain has frequently been observed in the parenchyma of 

 old dead stems of cotton, melon, and cowpea attacked and killed by 

 this fungus, and this stain when subjected to certain solvents behaves 

 in the same way as the red pigment of the perithecia. 



The formation of purple or other bright colors in the substratum, and 

 occasionally in the mycelium itself, appears to be common to many 

 Fusaria. Schacht observed it many years ago (Prings. Jahrb., Bd. 

 Ill, pp. 446-447). In potatoes attacked by wet rot he found the cavities 

 lined by Oidium violaceum Harting. This lining was dark violet to blue 

 black. This color he states to be due to the contents of the mycelium 

 and to the effect of the latter on the substratum. On addition of sul- 

 phuric acid the mycelium and spores became rose red. This change, 

 he thonght, denoted conversion of starch into sugar, for it took place 

 eveu inside of starch grains, and the color is similar to that which may 

 be obtained with sugar, albuminoids (Eiweissstoff), and sulphuric acid. 

 In dry starch attacked by the fungus and kept since 1855 he could, 

 however, get no reduction of the copper on warming in Fehling's solu- 

 tion. Oidium violaceum appears to correspond to the chlamydospore 



