458 THE AMERICAN NATURALIST.  [Vot. XXXII. 
more fungus than cheese. The author of these statements is Dr. 
Olav Johan-Olsen,' the well-known mycologist, who will be remem- 
bered as joint author with Drs. Brefeld and Istvánffy of two large 
volumes on basidiomycetous fungi (Hefte vii and viii of Brefeld’s 
Untersuchungen). For some years Dr. Johan-Olsen has been in 
charge of a royal Norwegian laboratory for the study of fermenta- 
tions, and has had unlimited facilities for experimental cheese-making, 
and also good opportunities for studying the cheese industry in 
France and other parts of Europe. He has spent ten years in his 
efforts to discover exactly how to make cheeses of special brands, 
has used up more than 110,000 liters of milk, and has made thou- 
sands of microscopic examinations and special cultures, more than 
500 different organisms having been isolated from a single variety 
of cheese. He now declares that his work has passed out of the 
experimental stage, and that he has discovered exactly how to 
make (by adding pure cultures of specified organisms to sterile or 
nearly sterile milk) well-known cheeses on a commercial scale. For 
example, one of the finest Norwegian cheeses is known as Gamme- 
lost. This cheese has a peculiar flavor, suggestive of apples, citron, 
and Camembert cheese, and always brings a good price. It is made 
by peasants in huts in the mountains, and there are so many uncer- 
tainties connected with its rule-of-thumb manufacture that only 10% 
of the product is first-class. By means of his pure-culture inocula- 
tions Dr. Johan-Olsen is now able to make this cheese on a large 
scale with a high degree of certainty, go% of the product being first- 
class, without bad odor, with very fine flavor, and with better appear- 
ance and better keeping qualities than the same cheese as ordinarily 
made. No less than 15,000 kilos of this scientifically ripened cheese 
was produced last year. For a long time Dr. Johan-Olsen’s experi- 
ments were barren of practical results, owing to his belief that the 
ripening of the cheese was due to bacteria. The abandonment of 
this hypothesis was followed by the discovery that the ripening and 
peculiar flavor of the most celebrated cheeses are due to the presence 
of fungi, and, what is still more interesting, to the joint action of 
several different sorts, one alone not being able to bring about the 
desired result. Until this symbiotic relationship was discovered 
he declares that hundreds and thousands of his cheese experiments 
miscarried, so that many of the cheeses had to be thrown away. In 
). Johan-Olsen, Die bei der P wirksamen Pilze, Centralb. f. Bakt., 
Parasitenkunde, u. Infektionskr., Abt. ii, Bd. iv, No. 5, March 5, 1898, pp. 161- 
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