THE BIO-CHEMISTRY OF ANIMALS AND PLANTS 119 



result — namely, that on hydrolysis phosphoric acid and inosite 

 are produced, these being the only two cleavage products — and 

 Posternack represented its constitution by the formula of an 

 anhydro-oxy-methylen-phosphoric acid : 



H\ /H 



(HO),OP .O-C-O-C-O. PO(OH) 3 



H/ \H 



according to which it contains the molecules of formaldehyde 

 and phosphoric acid. This formula explains the inosite forma- 

 tion, for three molecules of the acid would give rise to inosite 

 and phosphoric acid. The suggestion has, however, also been 

 made lately to assume a preformed inosite molecule. 



The investigation of the quantitative occurrence of this 

 substance, for which the short name "Phytin" has been intro- 

 duced, showed that 80 — 90 per cent, of the total phosphorus of 

 seeds is present in this form, the rest being mostly in lecithin. 

 The explanation which Posternack gives for the formation of 

 this substance in the plant is suggestive. As already demon- 

 strated by Schimper, phosphoric acid is transformed in the 

 leaves into organic phosphates, and this transformation depends 

 on the activity of chlorophyll under the influence of light. We 

 know, on the other hand, that the products of this " photo- 

 synthesis " are transported as soon as they are formed to the 

 parenchymatous and embryonic cells of the plant and deposited 

 in the organs which serve as the storage places for reserve 

 material. Posternack concludes therefore that the formation of 

 this substance takes place during the actual process of carbonic 

 acid reduction by chlorophyll, and that formaldehyde is the 

 initial substance formed which combines at once with phos- 

 phoric acid to form the new compound. During germination of 

 the seeds large quantities of inosite are formed from their phytin 

 store, and a ferment (phytase), which is responsible for this 

 transformation, has been isolated from the husks of rice, which 

 contain about 8 per cent, of phytin (Suzuki and Yoshimura). 

 According to McCollum and Hart, the blood and liver of animals 

 also contain a phytase, whilst muscle and kidney extracts are 

 without action on phytin. Gilbert and Posternack maintain that 

 the animal organism absorbs and retains a large amount of this 

 organic phosphorus compound. In connection with phytin, 

 which represents a vegetable organic phosphoric acid, an animal 

 representative of this type may be mentioned about which 



