570 GEORGE S. TERRY 



must be considered as the most important of the three, consists 

 in the removal and sectioning of the vertebral column of both 

 thyroidless and normal control specimens. The fixations used 

 were Flemming's solution, formalin and alcohol. All of these 

 gave excellent results but on the whole the Flemming material 

 was the most satisfactory. After the material was fixed it was 

 placed in a two per cent acetic acid solution for decalcification. 

 At first, the material was cut in sagittal sections and an attempt 

 was made to work out the various parts of the vertebral column, 

 but this soon proved to be more or less unsatisfactory because 

 of difficulty of interpretation, so it has later proved more satis- 

 factory to cut the material in transverse sections. By this 

 method there is no chance of misinterpretation of parts and the 

 orientation of the section is easily accomplished. 



The sections were all cut ten to fifteen micra in thickness 

 and the staining was done either with Meyer's haemalum or 

 Heidenhain's iron-haematoxylin, an alcoholic solution of eosin 

 being used in both cases as a counter stain. 



The third and last method of study, viz., the staining of the 

 cartilage and bone 'in toto' by the Lundvall method is especial- 

 ly useful in studying the bone and cartilage formation of the 

 hind legs. Ihe method is as follows, four parts of a saturated 

 solution of alizarine crystalizatum in 95 per cent alcohol was 

 mixed with one part of a very weak solution of either methyl 

 blue or toluoidin blue in 95 per cent alcohol. Specimens to be 

 stained were placed in the stain and kept in a thermostat at 

 32°C for from one to several days. They were then run up 

 through the alcohols and finally cleared in a solution of benzol 

 benzoate which must be so mixed that the index of refraction 

 of the mixture is the same as the index of refraction of the 

 tissue. In specimens which have been stained by this method 

 the bone takes on a red color while the cartilage takos on a sky 

 blue color. 



RESULTS 



The results of this work are based upon a study of twenty- 

 seven specimens, of which number twelve were thyroidless and 

 the remainder were controls. 



