THE ORIGIN AND DEVELOPMENT OF GASTRIC GLANDS. 6/ 



stonia, less so, on account of the great number of yolk spherules 

 obscuring all details ; while in the pig the complex structure of 

 the glands has rendered this especially difficult. 



TECHNIQUE. 



As both Amblystoma and Desmognathus abound in Ithaca a 

 complete series of each was obtained. The material was fixed 

 every other day and accurate measurements taken, so that a full 

 series, differing less than ^ mm. in total length between each, was 

 secured. Fixation was accomplished in various ways : Kleinen- 

 berg's picro-sulphuric (distilled water, 100 c.c.; sulphuric acid, 2 

 c.c.; picric acid to saturation, I part ; distilled water, 3 parts), Flem- 

 ming's chrome-acetic (water, 19 parts; i percent, osmic acid, 16 

 parts; glacial acetic acid, 2 parts; 10 per cent, chromic acid, 3 

 parts), picro-nitro-sublimate (sat. aq. sol. of picric acid, 500 c.c.; 

 water, 300 c.c.; nitric acid, 24 c.c.; mercuric chlorid to saturation), 

 and Perenyi's fluid (10 per cent. aq. sol. of nitric acid, 4 parts ; 95 

 per cent, alcohol, 3 parts ; y 2 per cent. aq. sol. of chromic acid, 

 3 parts) all gave fairly good results. But Carney's, modified 

 (glacial acetic acid, 30 c.c.; absolute alcohol, 30 c.c.; chloroform, 

 30 c.c.; nitric acid, 3 c.c.; mercuric chlorid to saturation), fixing 

 ten to sixty minutes, washing in 67 per cent, alcohol, then in 82 

 per cent, alcohol and iodin, and Gilson's, modified (glacial 

 acetic acid, 5 c.c.; nitric acid, 5 or 10 c.c.; 95 per cent, alcohol, 

 100 c.c.; sat. aq. mercuric chlorid, 400 c.c.), fixing three fourths 

 to twelve hours and washing as in Carnoy's, gave the most satis- 

 factory results. 



Many different stains were used, as methylene blue and eosin, 

 eosin and orange G, carmine-picro-nigrosin, thionin, safranin, 

 iron hematoxylin, but for staining sections on the slide chloral 

 hematoxylin with eosin as a counter stain gave the best results. 

 It was also found very advantageous to stain material fixed in 

 Gilson's or Carnoy's in toto. Eosin, restaining with hematoxylin 

 and eosin, or borax-carmine (Grenadier), restaining with hema- 

 toxylin, proved satisfactory. Staining in toto with Delafield's 

 hematoxylin and counter-staining in toto with a saturated alco- 

 holic solution of eosin yielded excellent results, as there is very 

 little danger here of overstating. (Small pieces were stained 



