94 CYTOCHEMISTRY OF ALDEHYDES 



in the cytoplasm and nucleus which are believed to contain pen- 

 tose nucleic acid. This investigation, however, has been made 

 in only a very preliminary way, and it by no means follows that 

 the colour which is developed under those conditions is necessarily 

 due to pentose nucleic acid. All that can be said is that the 

 procedure which is given has demonstrated the presence of a sub- 

 stance, which is normally masked in tissues, but which is brought 

 into a form which will react with periodate by a Feulgen-type 

 hydrolysis. 



Procedures of the type which have just been outlined will per- 

 mit the detection of a considerable variety of substances. Treat- 

 ment of a tissue with periodate followed by reduced fuchsin will 

 demonstrate the presence of a,£-glycol groups such as those of 

 glycogen. By using a Feulgen hydrolysis instead of periodate 

 oxidation, deoxynucleic acid may be demonstrated. An oxida- 

 tion carried out after hydrolysis will demonstrate certain types 

 of masked glycols such as those found in readily hydrolyzed 

 glycosides. It is also possible that a good deal of evidence can be 

 collected about the orientation of the hydroxyl groups in these 

 glycols. For example, the cis glycols can probably be prevented 

 from reacting with periodate by formation of the acetonyl com- 

 pounds, or, as Seymour Cohen has suggested to me, perhaps by 

 the use of borate in the periodate mixture. Trans hydroxy groups 

 do not readily form acetonyl compounds, nor do they have the 

 property, possessed by cds compounds, of forming a complex with 

 borate. Neither the acetonyl compound nor the complex with 

 borate is likely to react with periodate. 



By using procedures of this type it should be possible to obtain 

 very useful information about many of the natural polysac- 

 charides, including the polysaccharides present in the mucopro- 

 teins and intracellular matrixes. 



REFERENCES 



Bennet. 1940. .Am. J. Anat., 67, 151. 



Boscot, Mandl, Danielli, and Shoppee. 1948. Nature, 162, 572. 



Cain. 1949. Quart. J. Micro. Sci., 90, 411. 



Camber. 1949. Nature, 163, 285. 



Danielli. 1949a. Quart. J. Micro. Sci., 90, 67. 



19496. Quart. J. Micro. Sci., 90, 309. 



1950. Quart. J. Micro. Sci., 91, 215. 



