150 



HARDWICKE'S SCIE N C E-;G0 S SIP. 



Ehrenberg took tlie trouble, in liis thiid " Aid to 

 the Knowledge of Larger Organisms in the direction 

 of the smallest space," * to reduce most of the 

 forms established by me in the Synopsis to such 

 forms as were known to him ; but later he has 

 established the same forms as distinct species, in 

 his larger work on the "Infusoria." (Ehrenberg 

 did not publish his great work on^ the diatoms, 

 " The Microgeologie," until some few years after 

 Kiitzing had given his " Bacillarien " to the 

 world. This work is a monument of patient but 

 misdirected labour. The figures occupy 39 folio 

 plates, and are far better than any previously pub- 

 lished. The plan he adopted was to give a repre- 

 sentation of all the forms that appeared in the field 

 of the microscope, under a power of about 100 

 diameters. Grouped around the circle containing 

 these forms were separate drawings of them, 

 enlarged to about 300 diameters. This arrange- 

 ment, although useful in some respects, was open 

 to many objections, not the least of which was the 

 necessarily heavy cost and large bulk of the book, 

 for, not content with giving a large and small 

 representation of an object, it was repeated again 

 and again if it occurred in different deposits. — 

 F. K.) 



Kiitzing explains that the inferiority of his 

 figures was owing to the indifferent microscope he 

 used, and goes on to say that, however insufficient 

 his instrument, he made by it his most excellent 

 discovery, viz., the siliceous nature of the Diato- 

 macese, which soon led, through his friend Henri 

 Fischer, of Pirkenhammer, near Carlsbad, to the 

 other important discovery of the fossil deposit of 

 these organisms. "I had already, in my Synopsis, 

 called the substance of which these shells were 

 composed ' glassy,' because I had even then sus- 

 pected siliceous earth in these frustules. I com" 

 municated these to my friend Bilz, an expert 

 equally renowned as botanist and chemist, at the 

 same time asking him whether he would investigate 

 chemically specimens which I would send to him. 

 Bilz, however, declined the commission, stating 

 that he had no practice in the chemical investiga- 

 tion of microscopic objects." The matter rested 

 for a short time, until recalled to the author's mind 

 while investigating some Cliaraceaj. " I placed 

 gOme charse in dilute muriatic acid, in order to 

 remove the lime crust that was in the way of micro- 

 scopic investigation. In the course of examina- 

 tion I found that the soft chara stems were on the 

 outside garnished all over with diatoms, which were 

 not at all affected by acids. Notwithstanding the 

 twilight that had already commenced, I treated these 



* This title is somewhat obscure. The original is " Zur 

 Erkenntniss grosser Organisation in dor Richtung lies klein- 

 sten Raums." I understand it to mean an aid to the know- 

 edge of that large number of orgauisms occupying the 

 smallest space.— F. K. 



diatoms in separate watch-glasses with concentrated 

 acids, applying muriatic, nitro-phosphoric, and 

 ^uming sulphuric acids. The colour of the internal 

 parts became, under the first influence of the acids, 

 beautifully green ; but further investigations with 

 the microscope had to be postponed until the 

 following day. After a sleepless night, the exami- 

 nations were continued at the break of day, and at 

 eight o'clock on the morning of May Sth, 1S34, 1 

 had not only the full certainty of the siliceous 

 character, but also of the iron contents of the 

 diatoms. The diatoms which- had been brought 

 into contact with the concentrated acid had not 

 changed otherwise than that their internal matter 

 had disappeared." 



The author afterwards tried the action of soda 

 and a blow-pipe flame on a small mass of diatoms. 

 The solution of these in the soda followed completely, 

 and be obtained a perfectly transparent glass, which, 

 on cooling, appeared of a vitriol-green colour, indi- 

 cating the presence of oxide of iron. The interest 

 of the preface may be said to conclude here ; the 

 remainder of it is taken up with acknowledgments 

 of the kindness of various gentlemen who for- 

 wai'ded to him material from their own herbaria, 

 and a complaint that Ehrenberg did not acknow- 

 ledge, excepting very briefly and unsatisfactorily, 

 his discoveries of the siliceous nature of the 

 diatomaceous frustule, and the presence of iron in 

 them. Kiitzing says — "I was somewhat asto- 

 nished to see in Ehrenberg's large work on Infusoria 

 the iron of the Gallionellse mentioned as his dis- 

 covery, while he does not even allude to the fact 

 that I, in my essay sent to the Berlin Academy, 

 mentioned iron as a general constituent of diatoms. 

 It is easy to believe here in a ' turpinate.' " 



(Perhaps some of the readers of Science-Gossip 

 may be able to explain this expression ; I am unable 

 to do so myself.) F. K. 



A HALF-DAY'S PLANT-HUi\TING. 



1\yrY friend, Dr. M., having snatched half a day 

 '^-'- from his arduous professional duties, we 

 drove off from home at 1"30 p.m., with the intention 

 of visiting the great chalk ridge at Boxley, and 

 afterwards the village of Boxley at its foot, through 

 which meanders a small clear stream of water, 

 which issues from beneath the chalk escarpment. 



In our journey through the woods we made 

 numerous halts in order better to examine the 

 nature of the flora. The woods in this district are 

 grown for the sake of hop-poles, &c., and are cut 

 down periodically at intervals of from seven to ten 

 years. In the clearings thus produced the botanist 

 finds at all times a rich reward for the trouble 

 expended in hunting through them. The summer 

 after they are felled a great and varied selection of 



