Journal of Applied Microscopy. 



63 



stirred constantly and rapidly. The 

 saucepan was removed from the fire and 

 the solution neutralized. It was next 

 poured into wide-mouthed jars or flasks, 

 usually preserve Jars and jelly glasses, 

 and placed in the sterilizer, where it was 

 steamed for two hours or more, accord- 

 ing to convenience. Then turning off the 

 gas, I allowed the agar to cool slowly 

 over night without removing the cover 

 of the sterilizer. In the morning the 

 flocculi or sediment was found settled in 

 the bottom in a quite compact mass. 

 The upper portion was then removed 

 with a spoon, or, turning the cake out of 

 the jelly glasses, the cloudy portions 

 were sliced off with a knife. The clear 

 agar was then placed in the saucepan, 

 melted and tubed, and the cloudy part, 

 about ten per cent., thrown away. 



The advantages of this method over 

 that described by W. W. Alleger in the 

 January Issue of the Journal are: (1) 

 that by long steaming and subsequent 

 slow cooling all the precipitate is thrown 

 down and settles in a small space, (2) 

 by removing the clear portions from the 

 cold jelly there is no chance for any 

 flocculi to pass over as there is in siphon- 

 ing off the clear portions while the agar 

 is liquid. (3) the cloudy part is so small 

 a portion of the whole and contains so 

 little which would pass through the filter 

 paper, that it may be discarded with a 

 clear conscience. 



I have never found that long con- 

 tinued heating interfered with the nutri- 

 tive value of the agar, and I have fre- 

 quently steamed it for as much as six 

 hours. By the above method I have 

 invariably obtained clear jelly, and 

 often so clear that when tubed it was 

 difficult to distinguish from gelatin. 

 Marion Hamilton Carter. 



Cornell University. 



Some Points on the Technique of 

 Paraffin Imbedding. 



The following outline of a method for 

 paraffin Imbedding is not offered as an 

 entirely original process. It is the result 

 of experience in working upon various 

 botanical studies. It is believed that it 

 has the merits of ease and simplicity and 

 is especially adapted for those who lack 

 the expensive baths and ovens nosv 

 placed on the market. 



Success in imbedding botanical objects, 

 which are always more or less liable to 

 shrinkage, depends, first, upon the proper 

 fixation of the material, and, secondly, 

 upon gradual transfers from one fiuid 

 to another. To obviate the damage 

 caused by too sudden transfers, have 

 your work so arranged that something 



else can be done while allowing plenty 

 of time for each step in the process of 

 imbedding. 



Beginning with the fixed or pre- 

 served material, the first step is 

 the staining " in toto" and the 

 subsequent dehydration. For this pro- 

 cess the material, if there is a large 

 quantity and if each piece is of sufficient 

 size to be readily seen and conveniently 

 handled, is placed in small homeopathic 

 vials of from one to three drachms capa- 

 city. Where a great many different lots 

 of material are to be treated at the same 

 time, it is advisable to have each bottle 

 numbered, and this number may be 

 entered at the top of a page of the note 

 book, and under it notes made of all the 

 different processes to which it is sub- 

 jected. 



When imbedding very small objects it 

 is best to handle them as little as possi- 

 ble. Such material is very conveniently 

 contained during dehydration staining 

 and the alcohol-xylol mixtures in small 

 paper cornucopias made by rolling a 

 narrow strip of paper a little diagonally, 

 folding over the apex, and securing it 

 with a pin. The different fluids are pre- 

 ferably contained in wide-mouthed bot- 

 tles of at least one hundred cubic centi- 

 meters capacity. Into these the cornu- 

 copia with its contained material is 

 directly introduced. When transferring 

 from one fluid to another, the former 

 fluid should be drained off by laying 

 the cornucopia for a short time upon 

 absorbent paper. 



We will suppose that the material has 

 been stained, dehydrated, and has come 

 into pure xylol, and is ready for the 

 final transfer into paraffin. Flat-bot- 

 tomed watch glasses are then prepared 

 with a mixture of xylol and paraffin. 

 This should contain enough xylol to ren- 

 der it quite soft, yet not liquid. Upon 

 the top of this is poured a fresh layer 

 of xylol, and the objects are transferred 

 from the vials or cornucopias to the 



