24 



May \st, 1878. 



The following very iuteresting and valuaLle paper was read 

 by W. H. Hammond, Esq., of Milton Chapel : — 



A method of examining the crystals in situ in the leaves and 

 other parts of plants : Ever since I first began to use the micros- 

 cope, Plant Crystals have been objects of interest to me, not 

 only on account of their great beauty as " objects," espociaUj' 

 with the polariscope, but also because the}' open a new and 

 comparatively unexplored region of phytotomy ; in fact, except 

 in Professor Gulliver's ^^■ritiugs, they are hardly mentioned, or 

 very summarity dealt Avith, by other botanical writers. At first 

 I used to be content with a sight of them, after boiling and 

 Avashing parts of plants, but I scon became dissatisfied with 

 this method, andbegan tolook about forsome means of exa,mining 

 the crystals j ust as they grew in the different plants. Fortunately I 

 happened to look at a back nmnber (January, 1875) of " Science 

 G-ossi])," and came across a paper by the late Dr. Beatty, "On 

 decolouring and staining vegetable tissues for microscopical ex- 

 amination ;" other papers by Dr. Beatty came out afterwards, 

 and I obtained many hints from them on the subject. I am 

 often asked how my preparations are made, so I will describe 

 mv process of preparing and mounting for the benefit of otlier 

 Avorkers Avith the microscope, who are interested in these in- 

 teresting, but much neglected, marvels. The first thing to bo 

 done is to get the bleaching solution, and this may be very easily 

 prepared as follows : Equal weights of chlorinated lime and 

 common washing soda, both in fine powder, are put into a half- 

 gallon bo)ttle of cold water, and well shaken together, then left 

 to stand till the fluid is quite clear ; this is poured off gently 

 into another bottle, and a strong solution of washing soda added, 

 as long as a white powder is thrown doAvn. The mixture is 

 again left to stand till clear, and then poured off; this is the 

 bleaching fluid. The original substances in the first bottle may 

 be againtreated Avith cold water. Leaves and other tissues are 

 put in this liquid till bleached and semi-transparent ; large or 

 thick leaA-es are best cut up into small pieces. I find the small 

 round night-light glasses, Avliich may be bought for less than a 

 l^enny each, are very convenient for bleaching the tissues in and 

 also for dyeing and subseciuent soakings, covering them over 

 witli pieces of glass. It is not always convenient to preparo 

 mount leaves directly they ere gathered, so I always carry an 

 interleaved (with blotting paper) pocket book Avith me, with an 

 elastic band round it. Leaves are put into this Avhen gathered, 

 and by carrying it in the breast pocket of the coat, they are soon 

 dried by the warmth of the body. In the summer time several 

 books full of leavc:^ are collected ready for the long winter even- 



