50 THE MICROSCOPE. April 



place and the eyes in better condition than under the use 

 of alcohol. Reptiles, fishes and amphibians were nicely- 

 hardened- in one to ten, one to twenty, or one to thirty, 

 solutions according to the size of the object. The fishes 

 retained in great part their color, while the slime and 

 mucus covering them was rendered transparent. Of the 

 invertebrates, snails, jelly fishes, insects, spiders, etc., all 

 were well preserved. 



Of the various animal tissues, muscles and the brain 

 were quickly hardened, retaining the coloring matter of 

 the blood in the muscles, while in the brain the differen- 

 tiation between the white and gray matter was very evi- 

 dent. Fruits, flowers and vegetables of various kinds 

 were equally successfully preserved, the coloring matter 

 very little if at all impaired. Blum's conclusions regard- 

 the hardening of animal tissues may be summed up as 

 follows : 



Animal objects are hardened with shrinking, and with- 

 out losing their microscopic structure or staining proper^ 

 ties. 



The natural form and color are preserved. 



The eye remains much clearer than in alcohol. 



The mucus of slime-prodjicing animals is not coagulated 

 and remains transparent. 



The coloring matter of blood in tissues apparently 

 disappeared, but may be quickly restored by a high per 

 cent alcohol. 



These experiments of Blum were [intlunaking and 

 were quickly followed ])y those of Born, Tintner, 

 Kruckmann, Kenyon, Sadebeck, Mayers, and others 

 with seemingly favorable results as regards the preserv- 

 ing and hardening powers of this compound. Besides 

 these qualities it was especially v.aluable because of its 

 being non-poisonous, non-combustible, of a low freezing 

 point, and, what to scientists is quite a serious question, 

 very cheap. 



