17 



pound or nlbimiinoid, vi/, besides liavino- carbon, hvdro<>en, and oxy- 

 i>:on. it also contains considerable nitrogen and a littl(^ snli)hnr or 

 phosphorus or iron or other substances, thus fonnino- all>nnien, whose 

 chemical constitution is expressed by the approximate molecular 

 formula C,M,,,^,,0,.^,. or by weight C 53, H 7, N IG, O 22, S 1 

 per cent. Possibly this molecular formula is more properly written 

 3(C^.4H3yNB08), plus the addition of sulphur compounds such as to 

 make the Avhole become as before written. Mulder supposed that a 

 certain substance which he called proteine, and whose composition is 

 supposed to be C.joHobN^Oio, is the basal molecule of albumen; two 

 such molecules, Avith additional quantities of nitrogen, hydrogen, and 

 oxygen, combined with a little sulphur, phosphorus, iron, or other 

 mineral, make up, according to him, the constitution of the ordinary 

 albuminoid. But his views are not considered altogether acceptable. 



The constituent chemical elements contained in cellulose are ]:)i'e- 

 cisely the same as those of starch, wdiose fornuda is Ci;Hi,/)-,, but 

 the arrangement of the atoms and molecules among themselves is 

 undoubtedly very different, so that the physical and chemical proper- 

 ties of starch and cellulose are very diti'erent. Starch, diastase, and 

 cellulose may be considered as substances composed of molecules 

 whose internal structures are respectively more and more complex; 

 in the molecules of each of these substances the carbon, hydrogen, 

 and oxygen are in the same proportions relative to each other both 

 by number and by weight, but a molecule of diastase has twice and 

 one of cellulose three times as many atoms as a molecule of starch. 

 The composition of pure Avater is represented by the molecular 

 formula HoOj, or by Aveight H 11, O 89, so that starch may be consid- 

 ered as a compound of atoms of carbon Avith 5 molecides of Avater. 

 From the same point of vieAv diastase Avould be compounded of^l'2 

 atoms of carbon and 10 molecules of water, Avhile cellulose aa' ^;d 

 consist of 18 atoms of carbon and 15 molecules of water. These three 

 substances are therefore called carbohydrates, as though carbon com- 

 bined Avith Avater Avere to be considered as carbon combined Avith 

 liydric acid. This term is not to be confounded Avith the Avord " hydro- 

 carbon," which is applied to any compound of hydrogen and carbon, 

 Avhich, Avhen combined Avith Avater or other molecules, forms a vei-y 

 different series of chemicals, such, for example, as C,tH„, Avhicli is a 

 hydrocarbon and Avhen combined with 4 molecules of Avater or hydric 

 oxide forms alcohol, making the latter, as it were, a hydrate of a 

 hydrocarbon. 



The approximate percentages by weight of the cellulose found in 

 plants and vegetables dried at a temperature of 212° F. iuid the per- 

 2667—05 M 2 



