HARDWICKE'S SCIENCE-GOSSIP. 



201 



soon found the thieves to be rats. He saw one rat 

 carrying an egg in his fore-paws, and being dragged 

 along backwards by another rat. I was mentioning 

 this to a friend just lately, who said he had seen 

 a similar occurrence. It is probable I may now 

 have said quite enough ; at all events, my oppor- 

 tunities for studying the peculiarities of these 

 creatures seem to be over, for, their numbers con- 

 tinuing to increase, and their destructiveness being 

 almost unbearable, we introduced a cat, and, most 

 curiously, we have seen or heard nothing of our old 

 acquaintances since. W. C. H. 



HISTOLOGY. 



PROFESSOR -ALLAN THOMSON, in his 

 opening address in the Biological Section 

 of the British Association, said : — "I need scarcely 

 remind tbose present that it was only within a few 

 years before the foundation of the British Associ- 

 ation that the suggestions of Lister in regard to the 

 construction of achromatic lenses brought the com- 

 pound microscope into such a state of improvement 

 as caused it to be restored, as I might say, to the 

 place which the more imperfect instrument had lost 

 in the previous century. The result of this restor- 

 ation became apparent in the foundation of a new 

 era in the knowledge of the minute characters of 

 textureal structure, under the joint guidance of 

 R. Brown and Ehrenberg, so as at last to have 

 entitled this branch of inquiry to its designation, by 

 Mr. Huxley, of the exhaustive investigation of 

 structural elements. All who hear me are fully 

 aware of the influence which, from 1S38 onwards, 

 the researches of Schwann and Schleiden exerted on 

 the progress of Histology and the views of anato- 

 mists and physiologists as to the structure and 

 development of the textures, and the prodigious 

 increase which followed in varied microscopic ob- 

 servations. It is not for me here even to allude to 

 the steps of that rapid progress by which a new 

 branch of anatomical science has been created; nor 

 can I venture to enter upon any of the interesting 

 questions presented by this department of the mi- 

 croscopic anatomy ; nor attempt to discuss any of 

 those possessing so much interest at the present 

 moment ; such as the nature of the organized cell 

 or the properties of protoplasm. I would only re- 

 mark that it is now very generally admitted that 

 the cell-wall (as Schwann indeed himself pointed 

 out) is not a source of new production, though still 

 capable of considerable structural change after the 

 time of its first formation. The nucleus has also lost 

 some of the importance attached to it by Schwann 

 and his earlier followers, as an essential constituent 

 of the cell, while the protoplasm of the cell remains 

 in undisputed possession of the field as the more 

 immediate seat of the phenomena of growth and 

 organization, and of the contractable property which 



forms so remarkable a feature of their substance. 

 I cordially agree with much of what Mr. Huxley 

 wrote on this subject in 1853 and 18G9. The term 

 physical basis of life may perhaps be in some trifling 

 respect objectionable, but I look upon the recog- 

 nition of protoplasm, as a general term indicating 

 that part of the tissue of plants and animals which 

 is the constant seat of the growing and moving 

 powers, as a most important step in the recent pro- 

 gress of histology. To Haechel the fuller history 

 of this in lowest forms is due. To Dr. Eeale we 

 owe the fullest investigation of these properties by 

 the use of magnifying powers beyond any that had 

 previously been known, and the successful employ- 

 ment of reagents which appear to mark out its 

 distinction from the other elements of the textures. 

 I may remark, however, in passing, that I am in- 

 clined to regard contractile protoplasm, whether 

 vegetable or animal, as in no instance entirely amor- 

 phous or homogeneous, but rather as always pre- 

 senting some minute molecular structure which 

 distinguishes it from parts of glassy clearness. 

 Admitting that the form it assumes is not neces- 

 sarily that of a regular cell, and may be various and 

 irregular in a few exceptional instances, I am not 

 on that account disposed to give up definite struc- 

 ture as one of the universal characteristics of organ- 

 ization in living bodies. I would also suggest that 

 the terms formative and nonformative, or some 

 others, should be substituted for those of living and 

 dead, employed by Dr. Beale to distinguish the 

 protoplasm from the cell-wall or its derivation, as 

 those terms are liable to introduce confusion." 



WHITE VARIETIES. 



"TTTHATEVER may be the primary cause of 

 * » albinism, there can be no doubt but that it 

 becomes hereditary. The white varieties of wild 

 plauts are probably propagated by seed as readily as 

 those which receive the care of the floriculturist. 



Not long since I observed an extensive thickly- 

 set patch of the common thistle {Carduus arvensis), 

 var. flore albo, occupying the grassy border of a 

 chalky road, and fringing it for about GO feet of its 

 length. Every plant bore white blossoms, and not 

 a coloured head was to be seen amongst many hun- 

 dred individuals, except in the front and rear of the 

 line, where the blue cockades of the typical form 

 began to be intermingled with the white brigade. 

 As there was apparently nothing in the plot of 

 ground occupied by these plants different from that 

 in the vicinity, it cannot be that they were all due 

 to accidental contemporary variation ; but they must 

 have been the result of a previous seeding. White 

 varieties of thistles and other species are common 

 in the district, which lies on the chalk. I think I 

 have noticed albinism to occur more frequently in a 

 calcareous soil than elsewhere. R. B. S. 



