1896 THE MICROSCOPE. 51 



My attention was directed to this substance about one 

 year ago, through experiments made at the Laboratory 

 of the P]rie County Hospital by my interne, Dr. Helvie. 



Various tissues, as liver, spleen, placenta, lungs, heart, 

 muscles, and other tissues and organs were satisfactorily 

 hardened and preserved. Especially gratifying were the 

 results obtained with the umbilical cord, and other 

 myxomatous tissues. Instead of shrivelling u}» and be- 

 coming opaque as occurs when alcohol is employed, the 

 cord retained its normal size, was transparent and hard- 

 ened to such a degree that sections were easily and 

 perfectly cut with microtome. The intestines were 

 greatly shrivelled during hardening, but otherwise were a 

 success. 



These results induced me to try its virtues upon the 

 brain and spinal cord, and especially to find the earliest 

 time when a spinal cord so hardened could be imbedded 

 in celloidin and sections cut for staining and mounting. 

 A spinal cord which to all appearance was normal was 

 cut in pieces about one centimeter long and placed, sec- 

 tions of the cervical, thoracic and lumbar regions in 

 bottles containing a five per cent solution, ten per cent, 

 twenty per. cent and twenty-five per cent of Formalin. 

 At the end of seven days a section of the cord was taken 

 from each of these solutions and iml)edded it] celloidin, 

 then placed on the microtome. The cord was evidently 

 too imperfectly hardened, as no good cuts were obtained. 

 At the end of fourteen days the same procedure was fol- 

 lowed, likewise on the twenty-first day and twenty-eighth 

 days. From each of these intervals excellent cuts were 

 obtained ; the cord retained its external contour and ap- 

 pearance, but the differentiation between the white and 

 the gray matter was not as well marked as when alcohol 

 is used. These sections took the carmine stains nicely, 

 but less so the nigrosin, Pal and Weigert stains. The. 

 most serious action of the formalin on all of these sec- 



