SCIENCE-GOSSIP. 



found concentrated in corpuscles, £.<. in the 

 .dluscs, Solas UgunUH and Area note, in a 

 few Chaetopod worms (eg. the Polychaeta Glycera 

 and . in some Gephvrean worms (Plioronis, 



lsama. Htmingi.i), in some Xeraertine worms 

 atnlns), and in a few Echinoderms 

 ntllj, a sea-cucumber, and Ophiactis, a brittle 

 starfish) . These examples occur sporadically among 

 such widely-separated groups of animals that 

 haemoglobin must evidently have been indepen- 

 dently acquired several times in the animal 

 -iom. It is clear that the possession of it does 

 not in itself indicate any relationship. 



Arterial blood is scarlet owing to the haemoglobin 

 containing a rich supply of oxygen ; on the other 

 hand, the dark purple colour of venous blood is 

 due to an excess of carbon dioxide. Both gases, 

 however, are present in arterial as well as in venous 

 blood ; indeed, the former actually contains more 

 carbon dioxide than oxygen. The difference in 

 colour, therefore, is merely a question of varying 

 proportion, for an artificial solution of haemoglobin 

 changes colour from purple to scarlet when a 

 current of oxygen is passed into it. It is indeed 

 probable that the oxygen enters into a state of 

 unstable chemical combination with the haemo- 

 globin, and that the red corpuscle does not merely 

 hold it as a sponge. In this way the presence 

 of haemoglobin is an absolute necessity for the 

 more remote internal parts of the body to receive 

 a due supply of the vivifying oxygen and to get 

 rid of the waste carbon dioxide. Indeed, it is 

 doubtful whether vertebrates could have reached 

 their great size and dominant position in the world 

 ".out the possession of haemoglobin in its 

 valuable capacity for storing up oxygen. Haemo- 

 globin, however, is not confined to blood, but is 

 contained in the voluntary muscles of the higher 

 vertebrates (hence the red colour of raw flesh) as 

 U as in the tissue of the heart. Among fishes, 

 however, it is entirely absent from the muscular 

 je of the body, excepting in the fin muscles 

 -.he graceful little sea - horse (Hippocampus). 

 Among invertebrates it is found in the muscles of 

 tbe pharynx of a few molluscs (Chiton, Patella, 

 LUt tir.j. Paludma, Lymnjui and Aplysia), but, 

 strange to say, not in the blood of these creatures. 

 In the Chastopod worm, the sea-mouse (A 

 it is even restricted to the nerve cent 



In reviewing the habit , of those invertebrates 

 which possess this valuable coloured substance, 

 are able to infer that either hi they -.how increased 

 act pared to their nearest relation*, as in 



• r_a.se of the Neapolitan •■■ Ugumtn) . 



or (2) they II incei in 



ox . • easily obtained, a>i in the case of 



1 in the mud of stagnant pools. 1 

 I the ma: 



• • in blood 



muscle, or nerve, must be a valuable aid in such 

 adverse conditions ; or (3) there may be a combina- 

 tion of these reasons, as in the leeches, which 

 inhabit miasmic localities and yet show great 

 activity, leaping upon any unfortunate man or 

 animal invading their marshes. In the case of the 

 bloodworm, Professor Miall has shown that it 

 could live as long as five days in water that had 

 been deprived of its oxygen by boiling. The 

 view that haemoglobin has been primarily acquired 

 merely as an expedient in conditions unfavourable 

 to easy respiration, is supported by the fact that 

 the insect Chironomus possesses it only in its larval 

 (bloodworm) stage, but when it reaches its final 

 and winged state, its blood is colourless. The 

 disappearance of haemoglobin in the blood of the 

 perfect insect is indeed a highly remarkable fact ; 

 yet it is not surprising when, we consider how 

 thoroughly air is distributed to every tissue in an 

 insect's body through the air-tubes or tracheae. 

 The excessively delicate ramifications of these 

 tracheae extend into every muscle and even 

 penetrate between the cells of the eye and of the 

 nerve centres ; hence, since every part of the body 

 has direct access to the oxygen of the air, there is 

 no need for this gas to be conveyed by the blood ; 

 consequently the circulatory system in insects is 

 very imperfectly developed, and the blood is 

 colourless. 



Haemoglobin does not, however, stand alone in 

 the animal kingdom in its function of storing up 

 oxygen. In the blood of certain tube-forming 

 worms (Sabellidii and Se>pitlin<z) a greenish substance 

 chlorocruorin, occurs which has similar powers of 

 absorbing oxygen and yielding it up to all parts of 

 the body in need of it. It is, therefore, within the 

 range of possibility, that if the ancestor of the 

 vertebrates had developed chlorocruorin in its 

 blood in preference to haemoglobin, our blood 

 might be green, instead of red, and our admiration 

 aroused by a verdant instead of a pink complexion. 



.19, Hlomfield Road, Maida Hill, London, W.; 

 April, 1897. 



VtKKEs Great Lens.— After having taken 

 about five years to make and grind, the great lens 

 has been mounted and brought into use at the 

 Yerkes Observatory, Chicago. This enormous 

 lens has a surface diameter of forty-one and a- 

 half inches, and weighs no less than live hundred 

 and fifteen pounds. It was first used on the night 

 May ztst, in the exploration of Jupiter. Much 

 . pet ted from tin: astronomers who have control 



endl 1 ument. 



Photographic Material.— We havi recei ed 

 ( r ,,,, , George 1 toughton and Son, of 89, 



High 11 lborn, London, their very comprehensive 



raphii cameras, and • 

 otli- labli tii li u «d in the practice of 



phi , It I msalargeand bulky vol , 



1 [ be " ■ ful to both photo- 

 hi their mat< 



