154 



Methods in Plant Histology 



plasmodium from the slide. Acid fuchsin is a good stain for bring- 

 ing out the delicate strands of the plasmodium. Iron-alum haema- 

 toxylin, followed by acid fuchsin or erythrosin, brings out both nuclei 

 and cytoplasmic strands. 



Some of the foregoing methods are taken from an article by 

 Professor Howard Ayers in the January and February (1898) num- 

 bers of the Journal of Applied Microscopy. Other methods, with 

 directions for various experiments, are given in the same article. 



SCHIZOPHYTES (Fission Plants) 



BACTERIA (Schizomycetes, Fission Fungi) 



The methods of modern bacteriological technic are so numerous 

 and so specialized that we must refer to laboratory manuals 



for instruction in this subject. The 

 method given here will merely enable 

 the student to study the form and size 

 of those bacteria which are more easily 

 demonstrated. 



Foul water at the outlets of sewers 

 and such places will usually afford an 

 abundance of Coccus, Bacillus, Spiril- 

 lum, and Beggiatoa forms. Place a drop 

 of water on a slide, heat it gently until 

 the water evaporates, then stain with 

 fuchsin or methyl violet, dehydrate, 

 clear in xylol, and mount in balsam 

 (Fig. 27). 



The hay infusion is a time-honored 

 method for securing bacteria for study. 

 Pour hot water on a handful of hay, 

 and filter the fluid through blotting 

 paper. Place the fluid in a glass dish, 

 and cover with a piece of glass to keep 



out the dust. When the fluid begins to appear turbid, bacteria will 

 be abundant. The active movements are easily observed in a 

 mount from the turbid water. As the bacteria pass into the resting 



"i" '> ' 



111 



A 



ft 



C 



FIG. 27. Bacteria: A, Bacillus 

 anthracis, from a paraffin section 

 cut from the liver of a mouse; fixed 

 in chromo-acetic acid, stained in 

 methyl violet and Bismarck 

 brown, and mounted in balsam; 

 B, Spirillum sp., from a prepara- 

 tion stained in fuchsin* C, Staphy- 

 lococcus pyrogenes aureus, from a 

 preparation stained in gentian- 

 violet. X 535. 



