290 TOIVLE. [VOL. II. 



to two weeks. They were fixed in corrosive acetic, hardened 

 for two or three days in 95^0 alcohol, and then decalcified for 

 from six to eight days in a nitric acid solution (HNO^ sp. gr. 

 1.42, 2 vols. + H 2 O, 98 vols.) which was changed daily. They 

 were finally hardened again for three days in 95^0 alcohol, 

 embedded and cut. Some limbs were stained in toto with borax 

 carmine, but the best results were obtained by the method 

 used by Byrnes ('82), viz., staining on the slide in Delafield's 

 haematoxylin, followed by a wash of picric acid in absolute 

 alcohol. This latter method differentiates the muscle substance 

 very clearly. 



Eleven stages were preserved at the following intervals : 



Time of Operation. Time of Killing. Age of Stump. 



1. May 4, 1900.' May 14, 1900. 7 days. 



2. " " 18, " it " 



3. >l " " 29, " 22 " 



4. Oct. 22, 1899. NOV. 20, 1899. 29 " 



5. " Dec. 5, " 44 " 



6. '' " 15, " 54 " 



15, 54 



8. " " Jan. 5, " 75 



9. - " " 5, 75 



10. " " 20, " 90 " 



11. March 22, ' 151 " 



Transverse sections of this series were cut. Nos. i, 2, and 

 3 were stained with haematoxylin and picric acid ; 4, 5, and 6 

 with borax carmine ; 7 with borax carmine and picric acid ; 

 8 and 9 with Biondi-Ehrlich solution ; 2 10 and n with haema- 

 toxylin and picric acic. In addition, normal limbs were cut 

 and stained in a similar manner and used for comparison. 



Results. - - For convenience in description I shall consider the 

 sectioned limb as made up of three Regions : I, that between 

 the cut and the elbow; II, the Region just above the cut ; and 

 III, the growing end. In the earliest stages Region III does 

 not, of course, exist. 



1 It will be noticed that stages i, 2, and 3 were preserved later in the year, but 

 observations will be described in the above order. 



2 This stain was not successful, and the stages were replaced by one stained 

 with haematoxylin and picric acid. 



