CHAPTER VII 

 ORGANIC SUBSTANCES 



A. SACCHARIDES 



Sugars in their free form cannot be localized histochemically, 

 not even in frozen-dried material, because all known reac- 

 tions for them are far too slow. Very recently, Okamoto, Ka- 

 dota, and Aoyama^ have suggested a new method based on 

 the insolubility of Ba-glucose and Ba-lactose in alcohol. 



Method 



Fix very thin slices of fresh tissue in methyl alcohol satu- 

 rated with barium hydroxide for about 24 hours at icebox 

 temperature. Dehydrate with two or three changes of abso- 

 lute alcohol, carry tissue through two changes of chloroform, 

 and embed in paraffin. Mount paraffin sections directly on 

 the slide; use a minimum of egg-white-glycerol. Deparaffin- 

 ize section with chloroform, rinse in absolute alcohol, and 

 transfer to a 1 per cent solution of AgNOs in 80-90 per cent 

 alcohol; expose jar to direct sunlight. The insoluble precipi- 

 tate of Ba-sugar will be transformed into the corresponding 

 Ag compound and the latter reduced to metallic silver. Rinse 

 slide in distilled water, remove unreduced silver vvdth a dilute 

 solution of Na thiosulfate; counters tain and mount. A slide 

 rinsed thoroughly in distilled water before the silver bath 

 can serve as a control; only the difference between the two 

 slides is due to the presence of glucose or lactose. 



This is an untested method. It sounds promising, although 

 the accuracy of localization is probably only approximate. 

 Phosphates are very likely to give false positive reactions. 

 The method should be tried also on frozen-dried material. 



1. Okamoto, K., Kadota, I., and Aoyama, Z.: Taishitzu Gaku Zasshi, 

 14:35, 1948. 



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