FIBROUS CONNECTIVE TISSUE. 51 



be noticed, however, that the carbon of our preparations 

 shows decided variation, and it is also to be observed that a 

 diminution in the percentage of carbon is attended in each 

 case with a diminution in nitrogen. We may suppose that 

 Preparation No. 3 is the purest of our products, and it 

 is seen to agree most closely with the results obtained by 

 Loebisch, except in the content of sulphur. The mucin 

 from the submaxillary gland, as well as the snail mucin, are 

 both characterized by a comparatively high content of nitro- 

 gen, while the latter product also shows a higher percentage 

 of carbon. 



Our results seemingly justify the assumption that white 

 fibrous connective tissue contains more than one mucin, or 

 else that the mucin obtainable from this tissue is prone to 

 carry with it a certain amount of some other form of proteid 

 matter which the ordinary methods of purification are not 

 wholly adequate to remove. Our experience leads us to the 

 belief that the surest way of obtaining a pure mucin from 

 tendons, or at least one with a low content of carbon and 

 nitrogen, is to first extract the finely divided tissue with 10 

 per cent salt solution, then after removal of the salt with 

 water to extract the tissue with half -saturated lime-water hi the 

 proportion of two cubic centimeters for every gram of moist 

 tissue for about twenty-four hours at ordinary room tempera- 

 ture. This extract may be rejected, as it is very liable to yield 

 a mucin with a higher content of nitrogen and carbon. By 

 extracting the tissue a second tune with lime-water a mucin 

 may be obtained with a lower content of carbon and nitrogen, 

 as in our third preparation. It is purely an assumption, how- 

 ever, to say that this body with its lower percentage of carbon 

 and nitrogen is pure mucin. There is at the present time no 

 standard of purity with regard to this body, and it is quite as 

 probable that fibrous connective tissue contains two or more 

 mucins as that there is only one mucin in the tissue, and that 

 any deviation from the figures obtained by Loebisch or by us 

 in Preparation No. 3 is due to the presence of a larger or 

 smaller amount of proteid impurity. 



