72 Wilcox — Winter Condition of the Reserve Food 



is to remain in this mixture for about six hours or more. It is 

 then placed in pure chloroform for about the same time ; at 

 the end of which time it is transferred to a solution of paraf- 

 fine in chloroform and allowed to remain for about a week in 

 this solution. Complete infiltration in the melted paraffine 

 can now be secured in half an hour to an hour. By this 

 method beautiful ribbon sections are easily cut on the Minot- 

 Zimmermann microtome. These ribbons are fastened to the 

 slide by the usual albumen fixative. 



Staining was accomplished by one of the following methods — 

 the particular method depending upon the character of the 

 cell contents to which I desired to give special attention. In 

 the study of the leucoplastids and proteids crystalloids one of 

 the methods given by Zimmermann - * was followed. Plis acid- 

 f uchsin " method B " is well adopted to staining single sec- 

 tions while for staining on the slide the method of Altman is 

 better. Mann's methyl- blue-eosin method was found service- 

 able in the study of proteid crystalloids as well as for general 

 cytological purposes. This method was employed by Lily H. 

 Huief in the study of proteid crystalloids, and as the article 

 appears in a periodical that is not everywhere accessible I will 

 give the details of the method here. Two solutions are first 

 made as follows : 



cc 



A. 1 per cent solution of methyl-blue in water 35 



1 per cent solution of eosin in water _ _. 45 cc 



Water . . _ 100 cc 



B. 1 per cent solution of JSTaOH in absolute alcohol. 



Sections are to be stained for twenty-four hours in A and 

 then rinsed in water and dehydrated up to absolute alcohol. The 

 sections are now placed for a few minutes in thirty cubic centi- 

 meters of absolute alcohol to which a few drops of B has been 

 added. The JSTaOH is then removed from the sections with 

 absolute alcohol and they are then rinsed for one minute in 

 water. Red clouds are here given off and the sections become 

 blue again. They are now placed in water slightly acidulated 

 with acetic acid to deepen and restore the blue color and to fix 

 the eosin in them. They are now dehydrated, cleared with 

 xylol and mounted in balsam. In the special ctudy of the pro- 

 toplasmic counections several stains were employed but these 

 methods will not be given here. 



Before proceeding to the discussion of the results so far 

 obtained and their bearing on the general subject of the dor- 

 mant periods of plants, I will give in some detail the facts 

 observed in the study of two species, Liriodendron tidijpifera 

 and Pyrus mains. 



* Microtechnique (Trans.), p. 195-198, 1893. 

 f La Cellule, xi, 27-52, pi. i, '95-'96. 



