Before agar, microbiologists had experimented with other foodstuffs as microbial media. They turned to substances rich in the starches, proteins, sugars, fats, and minerals that organisms need for growth, testing with broths, bread, potatoes, polenta, egg whites, coagulated blood serums, and gelatine. However, none worked particularly well: all were easily broken down by heat and microbial enzymes, and their surface, once colonized, became mushy and unsuitable for isolating microbes.
Mahjong, Sudoku, free crossword, and more: Play games on Mashable。业内人士推荐WPS官方版本下载作为进阶阅读
，这一点在谷歌浏览器【最新下载地址】中也有详细论述
Pokémon TCG: Mega Evolution Ascended Heroes Elite Trainer Box，这一点在51吃瓜中也有详细论述
Фото: Svetlana Vozmilova / Globallookpress.com