SCIENCE-GOSSIP. 



" lignin " is but a cloak for ignorance. Two 

 substances, coniferin and vanillin, are always 

 associated with lignified cell-walls, and it is these 

 substances that give the colours with re-agents. 

 By prolonged boiling in alkalies these substances 

 can be extracted, and then the walls give the 

 reactions for cellulose, so that the cellulose basis 

 is simply permeated with these other substances. 

 Lignified cell-walls are hard, pervious to gases and 

 liquids, etc. Lignification commonly takes place 

 in the xylem vessels, parenchyma, selerenchyma, 

 etc. The middle lamella is commonly strongly 

 lignified, often partly suberized and changed in 

 other ways. 



In suberization, the secondary layer becomes 

 infiltrated with a substance (suberin), the deposition 

 of which in the cell-walls results in the formation 

 of cork. This substance (suberin) includes 

 really a number of different substances. The 

 middle lamella is commonly lignified. We can 

 extract the corky substances by warming in 

 alkalies and then treating with alcohol, and the 

 framework gives the ordinary cellulose reactions. 

 Cork-cells are impervious to water and gases and 

 will stand the action of strong H. 2 SO^ for a 

 considerable time. When a cell becomes corky 

 it becomes larger, and Strasburger has pointed 

 out that cork walls, under polarised light, show 

 colours due to stretching. Suberization takes 

 place in the periderm of stems and roots, the 



exodermis of roots, radial walls of endodermis.etc. 

 Cuticularization is a change closely related to 

 the foregoing, and cutin closely resembles, and 

 probably is a . form of suberin. The same 

 reactions (KOI I, etc.) that distinguish cork, 

 distinguish cuticularized tissue. 



Cell-walls may be converted into mucilage, that 

 is to say, mucilage may either come as a primary 

 substance from the protoplasm, or by degeneration 

 of the cell-wall. These vary in composition and 

 in reactions with micro-chemical reagents. 

 Some turn blue with iodine and H 2 S0 4 , but most 

 turn yellow. The middle lamella but seldom 

 undergoes this change (ex., Ivy), Mucilaginous 

 cell-walls when dry are hard and horny, but when 

 moistened become sticky and swell up. Mucila- 

 ginous cell-walls are common in the coats of seeds, 

 as linseed, quince, etc. This change may go on so 

 far as to result in the conversion of the cell-wall 

 into gum, soluble in water (ex., peach, plum, etc.) 



Frequently during the genesis of cells a sub- 

 stance is formed — not cellulose, but soluble in 

 boiling water and alkalies — to which is given the 

 name of pectose. This may be a forerunner of 

 cellulose. Another substance occurring in the 

 cotyledons of leguminous plants, palm and 

 liliaceous seeds, is known as amyloid. This is 

 allied to dextrose and gives the blue colour with 

 iodine without dehydrating agents. 



16, Hadley Street, Kentish Town, N.W.; 

 January 2,1st, 1895. 



PSEUDO-ALBINO SPARROWS. 

 By K. Hurlstone Jones. 



QEVERAL notices have of late appeared in 

 this paper referring to pseudo - albino 

 sparrows — I use the term for want of a better. 

 This abnormality of colouring is, as far as 

 my personal experience goes, by no means un- 

 common ; almost every winter I have observed, 

 from time to time, sparrows which represent this 

 curious condition. The feathers which have lost 

 their colouring matter are almost always the 

 primary feathers of the wings and the rectrices, 

 or quill feathers of the tail. Sometimes the whole 

 of the primary feathers in the wing are white, and 

 the same applies to the tail. Much more frequently 

 one, two, or three or more will be uncoloured and 

 the rest quite normal. Generally, I believe, the 

 metacarpal primaries are more liable to lose their 

 colour than the digital. I have also seen skylarks 

 presenting the same curious condition, but not 

 so frequently as sparrows, and we have in the 

 Manchester Museum a good specimen of a sky- 

 lark presenting uncoloured primary and tail quill 

 feathers. 



Observations are all very well as far as they go, 

 but only useful in that from them it is possible to 



B 



draw deductions. We require to know how the 

 condition has come about, and also we have several 

 rather important questions to ask about the con- 

 dition as it stands at the present day. With regard 

 to the origin of the condition, it is only possible to 

 theorize. Several theories suggest themselves to one, 

 all of which have this in common, that they point to 

 hereditary influence. In the first place, it is within 

 the range of probability that the ancestors of the 

 sparrows, and indeed of all the other birds, carried 

 uncoloured feathers, such feathers being obviously 

 less evolved than those which are coloured. It is 

 possible, presuming the above to be true, that 

 albinos revert to an original type, and that pseudo- 

 albinos are abortive attempts at reversion. 

 Secondly, it may have been necessary when the 

 winters were much more severe in this quarter of 

 the globe than they are now, for the birds to 

 change their plumage and lose the colouring matter 

 of their feathers in the winter, in order to gain a 

 protective colouration, just as the ptarmigan does 

 to-day. Reversion might take place as before. It 

 is significant with reference to this, that the 

 pseudo-albinos have at least, as far as personal 



