302 Journal of Agricultural Research voi. iii. No. 4 



Samples Nos. 3546a, 3546b, and 3546c were taken from a tub of 

 butter containing three small chumings. The tub had been kept in a, 

 refrigerator for three or four months and was very rancid. Since the 

 butter was designed for packing stock to be used in experimental work 

 on renovated butter, no particular care was taken in its manufacture. 

 It happened that the top layer (3546a) and bottom layer (3546c) were 

 heavily salted, while the middle layer (3546b) contained but a small 

 percentage of salt and a considerably higher percentage of water. The 

 top and bottom layers were free from mold; the middle layer showed 

 areas typically representing each of the types of moldiness described in 

 the following pages. 



TYPE-S OF MOLD FOUND IN SAMPLES 

 From the study of these and other available samples of moldy butler 

 three well-marked types of mold effects are distinguished: 



I. Smudged, or Alternaria, type. — In samples Nos. 3515, 3546b, 

 and 3554s, dark, smoky, or rarely greenish colors occurred in patches 

 which suggested soot or dirty-finger marks. Microscopic examination 

 showed mold mycelium with dark-brown or green walls on or under 

 the surface. Frequently these colonies are entirely submerged in the 

 butter. Sometimes hyphae were observed 4 to 5 mm. below the surface. 

 Spores were rarely found, but colonies transferred to culture media 

 grew freely and fruited normally. The dark-brown or black hyphee 

 were the most common and proved to be species of Alternaria. Where 

 a greenish color was seen species of Cladosporium developed. These 

 submerged areas suggest the appearances noted by Patterson (1900),' 

 and attributed to Stemphyliiim butyri Patterson. The occurrence of 

 Cladosporium in butter has been studied by Jensen (1900) and the 

 organism found was named by him "Cladosporium butyri." The 

 species of Cladosporium, however, are abundant upon all kinds of 

 roughage fed to cows, and the spores find entrance to the milk from 

 the handling of such feed by the milkers. One of the writers had access 

 to cultures made from many samples of cream by the bacteriologists 

 of the Storrs Agricultural Experiment Station some years ago. In 

 these cultures colonies of Cladosporium were so abundant as to indicate 

 that spores of these species remain with the cream after separation. 

 Species of Alternaria are very common in the same circumstances and 

 appeared in these cultures, but less abundantly. Their appearance as 

 colonies in the butter, therefore, is due to the ability of these species 

 to grow in the very severe conditions imposed by a mass of butler. 

 One of the writers has found a species of Alternaria growing and fruit- 

 ing in a box of shoe paste. Species of this group have also been iso- 

 lated from various forms of fat when small inclusions of water occur. 

 Few other graminicolous fungi seem able to produce colonies under 

 these conditions, though spores of many kinds are undoubtedly present. 



' Bibliographic citations in parentheses refer to '' Literature cited." p. 310. 



