20S BOTANICAL GAZETTE. 



the cover glass will accomplish the purpose, and this must not be neg- 

 lected while theoliject is under observation on the microscope, for it 

 there dries very quickly. Now to keep the slide and its culture-well 

 in good condition, you may have a little brass rack with two upright 

 pieces, say yC inch wide and three or four inches high for the ends and 

 these connected by horizontal rods, two of which shall form the plat- 

 form for one set of slides and two more half an inch higher for another 

 set, so you mav have several tiers over each other. Then on such a 

 rack you place your slide, put this on a dish with a little water, and a 

 bell-glass over all. Inside the bell-glass a bit of thin blotting paper 

 may be placed, which being made moist will aid in keeping the con- 

 tained air at point of saturation and so prevent drying of spores in 

 cover glass ; or, the slide with the culture well and its contained drop 

 and spores, may be left over night on the microscope if desired, to ob- 

 serve one particular spore or point, provided the well is thoroughly 

 moistened and then the bell glass which covers the microscope provi- 

 ded with the wet blotting paper, just as the bell glass over the rack. 

 So the whole instrument may be placed in a growing cell. Spores 

 may however be sown directly upon a glass slide, withnut the culture- 

 well, and cared for as those in the culture-well, but it is apparent they 

 are liable to .contamination from outside and undesired spores. One 

 great source of error with the beginner in spore culture is, that he 

 sows too many on a slide, and as they grow the whole becomes a con- 

 fused and tangled mass, which can hardly be said to teach any myco- 

 logical point with certainty. In this connection the student should 

 read pp. 239 to 242 of Prof. Bessej's admirable text book on Botany, 

 which I am almost tempted to say is the best work of its kind in the 

 English Language. It is a perfect marvel of compact, well consider- 

 ed, biological doctrines, and whatever else a student has he should 

 have this too. Leaf cultures, by which I mean producing a fungal 

 growth on a leaf suspected to contain the spores or the mycelium, is 

 simple enough. One merely needs to place the leaf on sand which has 

 been previously boiled to kill germs, and then allowed to cool. The 

 sand should not be kept wet or the leaf may rot too soon, but a simple 

 dampness maintained. To do this I find a good plan is to place the 

 sand and leaf in an unglazed clay flower pot dish, and this in a larger 

 table plate, then keep an eighth -of an inch of water in the latter ; it soaks 

 up through the clay dish and sand and moistens the leaf and air satis- 

 factorily. I have now a leaf which three weeks ago gave no sign of 

 perithecia, literally covered with a most promising crop of these or 

 like bodies, and the result brought about by the simple process I have 

 described. Of course over the leaf a tumbler or similar protection 

 must be inverted to prevent evaporation and to keep away stray spores. 

 If the plan proposed makes the sand too damp, simply use less water. 

 To obtain spores from such a leaf, one merely requires to invert a bit 

 of the leaf on a glass slide, then place a drop of water over the spore 

 producing part The moisture imbibed soon causes an expulsion in 

 sufficient numbers to continue the culture. If however one would 

 have a starting point of absolute certainty he must remove an isolated 

 perithecium, gently open it on the glass slide and allow the spores to 

 escape in a drop of water. From this he may reason and observe with 

 some assurance that he is right, and has the product of known spores. 



