702 



LIFE : OUTLINES OF GENERAL BIOLOGY 



of obvious interest, and with a little silk net one can fish plankton 

 forms in abundance, with strange larvae and what not. Returning 

 to the garden, its plants will be found to yield many interests: thus 

 the circulation of protoplasm in the stamen hairs of a Tradescantia 

 will never be forgotten, nor the yet more impressive circulation in 

 Chara or Nitella taken from a pond. So a drop of blood from a needle- 

 prick of the finger well rewards attentive study, and next the com- 

 parison of this with a similar droplet from the frog. Again see the 

 varied structure of hairs of different animals, the marvellous peri- 

 stomes of moss capsules on old walls and rocks, the simple structure 

 of moss leaves, and the interesting and useful complexity of the leaf 

 of the peat-moss Sphagnum — and so on indefinitely, as to the varied 

 scales of butterflies and moths' wings, the age-rings of fish-scales, 

 and whatever else attracts us. In short, in ways without number, 

 one can thus at once play and study with the microscope; and thus 



Fig. 104. 



Nuclear Chromosomes (CHR) in a Cell. A in the haploid and B in the diploid 



number. 



prepare for its more regular application and use. One is thus begin- 

 nmg anew with the old microscopists, and may rapidly recapitulate 

 their main discoveries, especially when thus aided by any of the 

 various introductory manuals, though it is best to begin even with- 

 out help of these. Enough at the outset to have a lesson or two on 

 the handling of the microscope and its objects from some more 

 experienced friend. Later on, the late Sir Arthur Shipley's Hunting 

 with the Microscope will give the beginner sound advice, at once 

 shrewd and entertaining. 



Yet the study of fresh material is often very disappointing, since 

 at first one sees so little; and thus recourse is had to methods of 

 fixing, staining, and clearing which bring out fine details of structure 

 in the cell. There can be no manner of doubt that the methods of 

 fixing and staining technique, of which we have previously given 

 a glimpse, have greatly contributed to the intimate modern know- 

 ledge of the microcosm of the cell. Without differential staining we 

 could have known little of the complicated processes of cell-division 

 and fertilisation. No small part of the modern advance in the study 

 of heredity has been due to a more penetrating knowledge of the 



