Method trek, etc. 



then passed through the higher grade: 

 rmine and haematoxylin used for staining. 

 >ceriiie and Alcohol-— 



This mixture, poured very slowly into the containing glass, 

 often gives very good results, both for anatomical and histologi- 

 cs Nicotine and Tobacco Smoke. — a. A solution of nicotine 

 (i g.) in sea water (i 1.), conducted into the vessel containing the 

 animal fully expanded in a half liter of sea water, by means of a 

 thread sufficiently large to empty the flask holding the nicotine 



b. The vessel containing the animal in an extended condition, 

 covered by a bell jar in which tobacco smoke is confined, until 

 the animal becomes completely benumbed. 



After being deprived of sensibility by either of these methods, 

 the creature may be killed in corrosive sublimate, or in picro- 

 sulphunc acid. 



D. Dr. Andres finds that in the use of chloroform, dropped 

 slowly into the water, or administered in form of vapor, macera- 

 tion usually sets in before the power of contracting is lost. Good 

 preparations of the internal parts may be obtained by injecting a 

 weak solution of osmic acid. The method of freezing has also 

 been employed with some success. For this purpose three ves- 

 sels are placed one within the other, the central one containing 

 the actinia, the middle one ice and salt, and the outer one cotton. 



The ice containing the congealed animal is dissolved in alcohol 



E. Maceration. — It is often important to see the cells of a tis- 

 sue in situ before freeing them with needles. In such cases Dr. 

 Andres proceeds as follows : 



1. Killed with corrosive sublimate. 



2. Left in 25 per cent, alcohol twenty-four hours. 



3. Soaked for a short time in a very thin solution of gum 



aralnc, then in a somewhat thicker solution, and finally 

 imbedded in a very thick solution. 



4. Hardened in 90 per cent, alcohol. 



5. Thick sections prepared for dissection with needles, lne 



sections are placed on a slide in water, which dissolves 

 the gum. 



(To be continued.) 



