242 THE AMERICAN MONTHLY [Sept., 



bacterial forms of fungi. These beings are thus almost every- 

 where for weal or woe, and the scientific modes of living that 

 are coming into vogue are having to recognize them as among 

 the most potent agencies that affect us. 



There are many modes of studying these interesting plants, 

 and those who wish to penetrate deeply into them will find many 

 technical guides to assist them. For the direction of such, a par- 

 tial bibliography of the subject will be appended. For a be- 

 ginning, however, fungi can be easily cultivated on almost any 

 organic substance which is kept moist and warm enough. In- 

 fusions of various sorts, such as : tea, hay, beef, oats, cracker, 

 and other such common stuff, made by heating the substances 

 to boiling and then setting them aside in tumblers covered with 

 glass plates, will in a few days be found to contain moulds 

 and perhaps also infusorial animals. Another mode of culture 

 is by the use of Pasteur's fluid.* This is made of sugar, am- 

 monium tartrate, and traces of sulphur and potassium salts dis- 

 solved in water. If this stands in a wide shallow vessel open 

 to the air lor a few days, the vessel will be covered with a white 

 film, this will soon become green in spots and then soon there- 

 after the green will cover the entire surface. The green color is 

 due to the spores which easily become dislodged and then float 

 in the air. From the green matter thus obtained you can cul- 

 tivate this mould under any conditions you may desire. 

 I. — Penicillium glaucum. 



This is the name of the green mould which is so well known 

 in all housekeeping. As far as the naked eye can take one, the 

 mould appears as a felted, green, or white membrane. In the 

 younger stages of the growth, it is in small spots scattered 

 everywhere on the culture fluid ; later, these coalesce and their 

 identity is lost. The surface of the older growths has a velvety 

 appearance. This is due to the innumerable "hyi)ha3," which 

 are minute threads rising above the mat like the "pile" of vel- 

 vet. If you blow forcibly over the green surface you can see a 

 powdery dust fly off. It is the conidia or spores which are 

 produced on the hypha\ 



*Pasteur's Fluid is made in the proportion: — 



Water 4150 parts; cane sugar, 750 parts; ammonium tartrate, 50 parts; 

 potassium phosphate, 10 parts; calcium phosphate, 1 part; magnesium sul- 

 phate, 1 part. 



