INTRODUCTION TO CETPTOGAMIC BOTANY. 23 



observations ' of the mere microscopist are the most delusive. 

 And even where the objects are higher, it is well that every 

 one whose attention is much directed to this greatly abused 

 instrument, should remember that if he wishes to penetrate 

 the secrets of nature he must look beyond his microscope, 

 a fact of which some microscopists of considerable reputation do 

 not seem at all aware.* The paramount importance of the 

 subject is to be seen in far different matters. 



14. The first great point is that the physiologist is able, in the 

 simpler Cryptogams, to study the several organs of which the 

 higher vegetables are composed, isolated and altogether removed 

 from other structures which may impede the view, or by their 

 rupture cause confusion. If, for instance, it is desired to ascertain 

 the mode of growth in cells, he will be able to appeal to the 

 simpler Algse, whether grumous or filamentous. In the one 

 he will be able to trace step by step the division of the pri- 

 mitive mother cell, with nothing to prevent his view in 

 consequence of the great transparency of the walls ; or if he 

 take one of the simple or branched Gonfervoe, he will be able 

 to assist at the origination not merely of two new cells from the 

 subdivision of one, but the formation of a new cell by pullulation 

 from the walls. Meanwhile he can ascertain exactly what changes 

 the endochrome is undergoing, he can watch the part which the 

 ojiioblast bears in the process, and can sometimes trace its parti- 

 tion. He can investigate in many cases, as in Zygnema and its 

 allies, or much more in Ghara and Nitella, the currents which 

 traverse the length and breadth of the cells ; he can trace thicken- 

 ing of the walls by the deposit of new coats, and in some cases the 

 shelling off of those which are effoete and have performed 

 their office. He can observe, moreover, the wonderful union of 

 separate filaments, the formation of a vital spore from the 

 union of the contents of neighbouring cells, and many other 

 points of interest, which throw more or less light on the 



* I allude here especially (amongst many like instances) to the utter 

 indifference with which Mr. Thwaites' great discovery of the conjugation 

 oi DiatomacecB -was received at the Oxford meeting of the British Asso- 

 ciation, by one whose whole reputation was built on the microscopic 

 study of these and other analogous organisms. 



