512 WHERRY AND YANOVSKY: MORPHINE DERIVATIVES 



seen on the plate-like crystals; the optic axial plane being 

 parallel to the surfaces of the plates, no interference figure is visi- 

 ble in most cases, but when flakes are broken across and tilted 

 up, partial figures can be seen, the axial angle 2E being large, 

 about 110°; sign — ; and dispersion strong, with 2Er> 2Ev. 



On comparing the axial ratios of these alkaloids, it is at once 

 seen that there are certain relationships among them, and it 

 seemed of interest to calculate and compare their topic axial 

 ratios. For this purpose their specific gravities were determined 

 approximately by suspension of clear crystals in mixtures of 

 sassafras oil and small amounts of bromoform, a combination 

 selected because it was found to attack the substances but slowly ; 

 and the gravity of the Hquid in each case was then measured 

 by a Westphal balance. The results are presented in table 6. 



The topic axial relations exhibit certain interesting features, 

 and permit of determining in which direction in the crystals 

 substitutions or additions occur. Thus, comparing anhydrous 

 codeine with its monohydrate, it is seen that the addition of the 

 water takes place in the vertical direction, producing a 40 per 

 cent increase in axis 00 while x and lA both decrease about 

 15 per cent. Comparing the three monohydrates, of mor- 

 phine and of its methyl and ethyl esters, it comes out with 

 equal clearness that the CHo groups enter along the front-back 

 axis, for the value of x increases 50 per cent from morphine to its 

 methyl ester, and 40 per cent more from the methyl to the 



