Hardesty, Medulla Spinalis of the Elephant. 141 



identical scheme devised by him, so that measurements made 

 from the two specimens may be compared. 



KopscH tabulates measurements from fourteen of the en- 

 tire forty-one segments of his specimen. With the addition of 

 Kopsch's measurements from the intumescentialumbalis, the au- 

 thor has included in Table II only such of the sections measured 

 by KoPSCH as would, by position, compare with such measure- 

 ments as the author was enabled to make from the material at 

 his disposal. In order to present measurements from a greater 

 number of segments of the localities available, the sections 

 chosen by the author for measurements are from segments in- 

 tervening between those from which Kopsch recorded measure- 

 ments. The author's measurements are placed in parallel col- 

 umns to those of Kopsch and are set in heavier type in order 

 to be distinguished. 



Kopsch's measurements were made from photographs of 

 free-hand sections of material which had remained two years 

 in Muller's fluid and then washed for two weeks in 70 per 

 cent, alcohol. The action of the Muller's fluid, in all proba- 

 bility, resulted in a slight increase in the volume of the tissue, 

 which increase was hardly reduced by the subsequent action of 

 the alcohol. The sections were twice enlarged in the photo- 

 graphs and consequently the measurements obtained were re- 

 duced one half before recording them in the table. 



On the other hand, the author's measurements were made 

 from stained sections of material which had been fixed in ten 

 per cent, formalin, dehydrated with alcohol and embedded in 

 celloidin. Formalin produces a swelling by causing the tissue 

 to take up water, and the subsequent action of the alcohol in 

 dehydration produces an appreciable shrinkage of the tissue, re- 

 gardless of precautions taken in the process. Measurement of the 

 block while in formalin and then of the section after embedding 

 in celloidin shows that this shrinkage may amount to as much 

 as five per cent, of the diameters of the block while in formalin. 

 How much, or whether at all, the dimensions of the dehydrated 

 formalin material vary from the normal dimensions in the fresh 

 state could not be determined with the material in hand. It is 



