464 C. CLIFFORD 1)0BET,L. 



and so help to clear away the confusion wliich now snrvounds 

 these bodies. 



Metachromatic granules are found not only in man}' 

 Bacteria, but also in Fungi, Alga3, Cyanophycea?, Protozoa, 

 and probably in many of the " liiglier " groups of animals and 

 plants. Their presence in Bacteria can therefore not be used 

 as evidence of the affinities of this group. 



Regarding the chemical and staining properties of ihese 

 granules, we now have a considerable mass of information — 

 chiefly from the work of Guilliermond, Grimme and A. Meyer.^ 

 Their most characteristic property is that they stain red with 

 many blue or violet stains (e.g. methylene blue, htematoxyliu, 

 etc.). After fixation they have a strong affinity for so-called 

 "nuclear" stains — which has given rise to their confusion 

 with chromatin. 



Chemically considered, the metachromatic granules are 

 probably to be regarded as composed of nucleic acid combined 

 with an organic base (cf . Meyer, Guilliermond). 



The biological significance of the metachromatic granules 

 appears to be definitely decided. They are non-living 

 (metaplasmic) reserve material. They are not living 

 morphological derivatives of either nucleus or cytoplasm, but 

 merely stored up food substance. The evidence for this 

 appears to me overwhelming. The most important fact has 

 been established, 1 believe, that they are not a constituent of 

 the living protoplasm: they are transient, non-living 

 elements of the cell. That they are in any Avay an index of 

 the virulence of the oi-ganisms containing them, as maintained 

 by Marx and Woithe (1900), is negatived by the work of 

 AscoH (1901), Krompecher (1901), Gauss (1902), Schumburg 

 (1902), Ficker (1903), Guilliermond (1906) and others. The 

 biological distribution of the granules throughout other 

 organisms also speaks strongly against such a view. 



It might be urged, with some justification, that the 

 " chromidial nucleus " descinbed in Bacteria by Schaudiun, 

 Guilliermond and myself is really nothing more than a diffuse 

 1 See also Eisen])eri,' (1010). 



