HALF-AN-HOUK AT THE MICROSCOPE. 247 



EXPLANATION OF PLATES XXVI. AND XXYH. 



Plate XXVI. 

 Senecio vulgaris. 

 Fig. 1. — Seed divested of half its plume, x 20. 

 2. — Hairs of plume, x 240. 

 3. — Hairs of Achcenium, with spiral fibres, x 240. 





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 >> 



Plate XXVII. 



4. — Section of Germen, with Raphides in situ, x 240. 



5. — Section of Testa, with ditto, x 50. 



6. — Section of Leaf, with Inuline Crystals, x 240. 



7. — Apex of Bract, x 54. 



8. — Florets to explain Cross-Fertilisation, x 12, 



1l3alf:^an*=1bour at tbe fIDicroecopc, 



Mitb /Il>i% Uutfen Mest, jf.X,5., ff^lR./ID.S., etc. 



Black-Ground illumination is a poor way of getting at the facts 

 which a specimen may disclose ; so also is polarising. An exami- 

 nation should be commenced with the lowest power likely to be 

 suitable ; then higher and higher powers applied, when probably at 

 each step new facts will be discovered — i.e., if the object be not 

 spoilt by being mounted merely with the intention of looking 

 pretty. Our object should be to see things as exactly as possible as 

 they are in life. Crushing an object with spring clips is diametri- 

 cally opposed to this, and should be in a general way avoided. 

 Use potash in the preparation of an insect if needful, but if you 

 do, try to get it into its natural form afterwards. Don't think 

 that perfection is to get things as painfully flat as possible — that 

 is the most unlike nature that can be. 



Seeds, Paulownia imperialis. — This furnishes one of the most 

 beautiful objects for displaying the powers of the binocular 

 microscope which I know. The pleasing effect of these exqui- 

 sitely delicate lace-like wings is very great. The natural order, 

 ScROPHULARiACE/E, to which the plant belongs, furnishes very 



