492 IOWA ACADEMY OF SCIENCE Vol. XXV, 1918 



Growth was hixiiriant and the entire medium was deeplv col- 

 ored. According to Buehaiian, Monascus purpureus is used by 

 the Chinese in the preparation of "red rice." which is used as 

 food. 



The green mold was isolated and identified as PeniciUium ro- 

 gue fort i Thom, which is often referred to in dairy literature as 

 PeukiUium glmtcum- Link. It is always found on Roquefort 

 cheese and also occurs on other cheeses. The mycelium is char- 

 acteristically green or grayish green and becomes a deep bro^^^l 

 when two to four weeks old, if exposed to the air. The medium 

 is not colored. It grows equally well on Raulin's medium and 

 on silage juice agar. 



From the experience of the writer it seems that these two 

 molds are practically the only ones found in well preserved sil- 

 age below the surface. Other molds have been isolated from sam- 

 ples of silage, but the fact to be considered is that moldy silage 

 is not generally found except where the silage was not moist 

 enough to be well packed and thus thorouglily exclude the air. 

 If air is not excluded, various molds may be found, but such 

 conditions are not considered here. 



TOXICITY TESTS. 



Following the methods used by Gortner and Blakeslee.^ water 

 extracts of the mycelium of these two molds were made by grind- 

 ing the mycelium, gro^vn on agar, with pure ignited sand and 

 filtering with suction. The filtrate was heated just to boiling ana 

 quickly cooled, taken up in a sterile glass hypodermic syringe 

 and injected with the usual precautions into the ear veins of rab- 

 bits. Various concentrations and amounts, up to 2 c.c. of the 

 concentrated extract, were injected into four different rabbits. In 

 no case was any injurious effect noted. In order to check the 

 procedure, cultures of Rhizopus nigricans, the mold used by 

 Gortner and Blakeslee, were grown and water extracts made a^ 

 above described, using amounts of Rhizopus mycelium compar- 

 able to those used as mentioned above. The characteristic reac- 

 tion, followed bj' death in a few hours, was obtained Avhen the 

 extract was injected into the ear of one of the rabbits. 



After going on short rations for a day, two of the rabbits read- 

 ily ate silage on which these molds (.1/. purpureus and P. roque- 

 fo-rfi) had been gro^^^l. One cf the rabbits consumed in two days 



'Ob.ser\-ations on the toxin of Rhiscpus nigricans, Amer. Jour, of Physiol 

 V'ol. 34, pp. 3.53-367, 1914. 



