404 STATE BOARD OF AGRICULTURE. 



The cream white, slowly liquefying yeast is found once in sample XIII, and 

 once in XX. It has very regular elliptical cells 5 x 7^ in size. The growth 

 on lactose agar is abundant. A yellowish slime is produced 2-3 mm. thick, 

 spreading over the whole surface of the agar. Gelatin begins to become 

 liquefied after 1-3 weeks. Milk shows no change. 



The small irregular yeast is very different in size, the smallest cells are al- 

 most round and about 2/« in diameter, sometimes even smaller. The aver- 

 age cells are elliptical or oval and about 3 x 4/i in size. Some larger cells 

 are usually, but not always found. Many of these cultures tend to produce 

 elongated cells — sausage forms — which sometimes reach the length of 20 

 and 25/i; this tendency is usually a peculiarity of all the cultures of the same 

 butter sample, and it seems that the yeasts of different dairies are different 

 varieties of the same species. The agar streak culture is glistening wliite, 

 and not characteristic. There are no crystals, and there is no difference 

 between ordinary and lactose agar. In gelatin there is arborescent growth, 

 but no liquefaction; in broth and wort, turbidity, a ring around the surface 

 of the liquid, but no distinct scum. Milk stays neutral or turns very slightly 

 alkaUne. 



The perfectly round yeast has regular cells of 4-5// diameter. Its nu- 

 trient agar streak culture has a slight iridescence like mother-of-pearl; it 

 has also parallel lines across the streak and on lactose agar, abundant growth 

 over the whole surface (except XlXf). There are crystals in ordinary agar, 

 not in lactose agar. The gelatin stab is not arborescent, but filiform or 

 beaded. Wort is clear, with an abundant flocculent sediment and a very 

 prominent pronounced ring around the surface. We found this round yeast 

 in 20 different butter samples, 15 of these samples came from the cold storage 

 a, which was always kept above the freezing point. Only 5 of the yeasts 

 came from the other cold storage. This yeast therefore seems to prefer 

 the warmer storage, and is able to outgrow the small irregular type. 



The maltose fermenting yeasts belong certainly to different species. The 

 yeasts of the lots IX and XIV ferment maltose only, and are not at all in- 

 fluenced by lactose. The yeast X ferments maltose only, but grows abund- 

 antly in the presence of lactose. It also liquefies slowly after 20 or 30 days. 

 The other five yeasts ferment maltose as well as lactose — they are the three 

 yeasts of XI and one each of XIV and XXII. Four of these are small 

 elliptic or round yeasts, 3x4// and 4 x 5/« in size. Yeast Xlb is larger, 

 4 X 5-5 x 6/i, and has many granules. Yeast X has elliptic cells 5 x 6/i and 

 larger, mixed with small round cells 3 x 3/<. Yeast IX is somewhat larger, 

 4 X 6-4 X 8/i is the predominant size. Yeast XIV is perfectly irregular 

 with inany sausage forms. 



STREPTOTHRIX. 



The micro-organisms which were named Streptothrix may perhaps be 

 something different. Migula says that most of the organisms described 

 as Streptothrix do not belong to this family at all. We believe, however, 

 that our germs are identical with the Streptothrix found by Reinmann and 

 Jensen in butter, and therefore used the same name. Besides the one quite 

 frequent white species, which liquefied gelatin and curded and digested 

 milk with neutral reaction very rapidly, we found twice a chalky-wliite 

 species and three times a brown species. In our tables we did not make a 

 distinction between these three kinds. 



The three molds which were found quite frequently were Oidium lactis, 

 Penicillium glaucum, Aspergillus glaucus. 



