December 15, 1916] 



SCIENCE 



867 



opinion as to the nature of the latter fraction. 

 The efforts to isolate it for detailed study have 

 not been successful thus far, but the work in 

 this direction is continued. 



The volatile acid given off, of which acetic 

 is the more predominant constituent, does not 

 represent a component part of the molecule. 

 It is a decomposition by-product of the glu- 

 cose. It is possible to lower greatly the yield 

 of sugar by hydrolyzing chitin with strong 

 acid or by raising the temperature or increas- 

 ing the duration of the hydrolysis. A great 

 evolution of volatile acid from the chitin will 

 occur simultaneously. The very small quan- 

 tity of acid formed even in the cold must be 

 likewise attributed to the slow oxidative action 

 of the strong sulphuric acid which must be 

 used in order to dissolve the chitin. 



Assuming that the empirical formula for 

 chitin is correct (elementary analyses are in 

 progress now to verify this) we may interpret 

 the above facts in its light, without recourse to 

 the hypothesis that the chitin molecule con- 

 tains an acetyl group. If we assume that the 

 chitin is a polymere of eight CsH^NO,, mole- 

 cules, this should yield on hydrolysis seven 

 molecules of glucosamin, C H 13 N'O B , one mole- 

 cule of glucose, C c H ]: ,O e , and one molecule of 

 the yet unidentified nitrogenous fraction. As 

 the amino groups are cleaved off in the hydro- 

 lysis, we get altogether eight glucose mole- 

 cules to seven ammonia nitrogens and one 

 residual nitrogen. Theoretieally, then, the 

 chitin molecule should yield 81.1 per cent, of 

 glucose, and 87.5 per cent, of amino nitrogen 

 and 12.5 per cent, of nitrogen in a stable com- 

 bination. The facts obtained by hydrolysis 

 agree remarkably with these theoretical expec- 

 tations. 



I could hardly enter here upon a discussion 

 of the bearing of these results further than to 

 say that monoacetylglucosamine, or for that 

 matter monoacetyldiglucosamine, have no 

 relation to chitin. They are secondary prod- 

 ucts, and are formed after the chitin molecule 

 has been broken down by the action upon it 

 of the sulphuric acid. 



S. Mokgulis 



The Creighton Medical College, 

 Omaha, Neb. 



OUTLIERS OF THE MAXVILLE LIMESTONE IN 

 OHIO NORTH OF THE LICKING RIVER 1 



It is well known to those familiar with Ohio 

 geology that the Maxville limestone is the 

 uppermost formation of the Mississippian Sys- 

 tem found in the Ohio scale, that its outcrop 

 is limited in extent, patchy in character, and 

 that the overlying Pennsylvanian beds rest 

 upon it unconformably. Up to the present, all 

 the known outcrops of this formation occur 

 south of the Licking Eiver in central Ohio 

 and they lie in a belt ten or twelve miles wide, 

 which extends from the above river on the 

 north to the Ohio River on the south. 



It has long been supposed that the forma- 

 tion once extended northward to northern Ohio 

 and was removed by late Mississippian erosion. 

 The supposition was based upon the presence 

 of lime cobblestones more or less silicified 

 which are found in places in the bottom of 

 the Coal Measure basal conglomerate, and 

 which were said to carry Mississippian fossils. 

 Since no other Mississippian limestone was 

 known to occur in the state, it was concluded 

 the cobble stones must have been derived from 

 the Maxville. 



It is the purpose of the writer to (1) point 

 out the northward extension of this limestone, 

 to (2) throw further light on the origin of 

 the cobble stones, and to (3) emphasize a rea- 

 son for the absence of the limestone in north- 

 ern Ohio. 



Beginning at the Licking Eiver various 

 outcrops of this limestone were found as far 

 as forty miles north of the city of Zanesville 

 in a belt ten to twelve miles wide. They in- 

 variably occur in isolated patches, are uncon- 

 formable with superjacent beds, vary in thick- 

 ness from two to nine feet, and are clearly ero- 

 sion remnants of a former continuous stratum. 

 Where it is not weathered it presents the same 

 blue-gray, fine-grained, compact character 

 found far to the southward. In places it is 

 fairly fossiliferous, and when fully weathered 

 there remains a residual ocherous earth of 

 deep yellow to chocolate color, mingled with 

 silicious concretions. The latter weather 



i Read before Section E, A. A. A. S., Columbus 

 meeting, 1915. 



