MYXOMYCETES AND SCHIZOPHYTES 209 



cent solution. The material may be kept here indefinitely, but after 24 

 hours it is ready for use. If the forms are small, like Anabaena, smear 

 a sHde lightly with Mayer's albumen fixative, as if for paraffin sections, 

 add a drop of the material and allow it to dry overnight or for 24 hours; 

 then immerse the slide in strong alcohol for a few minutes, and pro- 

 ceed with the staining. Cyanin and erythrosin form a good combina- 

 tion for differentiating the granules. Delafield's haematoxylin, used 

 alone, stains some granules purple and others red. Iron-alum haema- 

 toxylin is excellent for heterocysts. With patience, these Wasserhliithe 

 forms may be stained in iron-haematoxylin and brought into Venetian 

 turpentine, from which they will yield much better preparations than 

 can be secured by the drying-down method. 



Sometimes Anabaena, mixed with Gloeothece or Gloeocapsa, occur 

 floating in gelatinous masses which hold together fairly well so that it 

 is easy to fix in the chromo-acetic-osmic solution recommended for 

 Oscillatoria, stain in iron-alum haematoxylin, and follow the Venetian 

 turpentine method. 



With such material we have tried a more expeditious method with 

 excellent results. After staining in haematoxyhn, we have used a series 

 of alcohols, 21, 5, 10, 15, 20, 30, 40, 50, 70, 85, 95, and 100 per cent, 

 allowing only 3 or 4 hours for the entire series. Then use mixtures of 

 clove oil and absolute alcohol, beginning with 1 part clove oil to 4 parts 

 alcohol, followed by equal parts clove oil and alcohol, then 3 parts 

 clove oil to 1 of alcohol. At this point, stain in orange dissolved in 

 clove oil. Drain off the stain and transfer to pure clove oil. Then place 

 the material in thin balsam, about 1 part of the balsam used for 

 mounting to 3 parts of xylol. Here the material may be kept 'indefi- 

 nitely. Mounts may be made in balsam from this stock. Figure 42 

 was drawn from material prepared in this way. 



