SCIENCE-GOSSIP. 



entirely discontinue the naming of species after 

 persons, however eminent in their own branch of 

 study. I am afraid a person's name is frequently 

 given as much out of indolence in searching out a 

 fitting title, as the desire to honour a specialist. It 

 is evident that scientific advancement is best 

 served by purely descriptive names, though the 

 personal title-giving is somewhat less reprehensible 

 for botanical purposes, bearing in mind the horti- 

 cultural aspect ; in that connection the malpractice 

 is very frequent. 



The theory of priority based on types is at first 

 sight good ; but it is, I think, extremely questionable 

 whether in the case of the resuscitation of a 

 lost-sight-of type, in conjunction with the law of 

 priority, it is not better to allow usage to prevail. 



Where no type has been definitely assigned by 

 the erector of a genus containing in its primitive 

 condition a heterogeneous collection of species, I 

 hold a succeeding author well within his rights 

 when creating new genera from the old material, 

 in making not only the first species on the list the 

 type of the old genus, but any of the contained 



species most agreeing with the old generic 

 characters. The first-named method is, however, 

 usual. Thus, in odonata, I consider Leach to 

 have definitely fixed several important types by 

 the creation of his genera Gomphus and Calopteryx, 

 rather than that, for instance, the type of the 

 latter were fixed by Latreille's usage of Linnean 

 material. The German code favours my view, 

 which, of course, in the main, brings us back to the 

 desirability for keeping to the use of established 

 names and popular types rather than in all cases 

 the author's own. 



The wish of all naturalists must be to see the 

 various open questions of nomenclature finally 

 settled, for both present and future satisfaction 

 and future advancement, and it is to be hoped that 

 this will soon be done through the agency of 

 an International Congress of interested men of 

 science. Shiftiness of nomenclature is one 

 of the greatest stumbling-blocks in the way of 

 the study of species and the encouragement of 

 students. 



Stoke Newingtott; May 15th, 1897. 



THE COLOUR OF BLOOD. 



By Felix Oswald, B.A. Lond. 



" "DLOOD-RED " is so familiar an adjective of 

 colour, as to readily convey the impression 

 that the blood of all animals is red. Such, 

 however, is far from being the case, for although the 

 possession of red blood is a characteristic common 

 to all vertebrates) 1 ) ; yet when we come to examine 

 the invertebrates, which are far more numerous 

 both in species and individuals, we find that blood 

 of a red colour is a relatively rare occurrence. 

 In the majority of cases it is colourless ; but it 

 maybe even green, blue, or yellow. 



It has often been a subject for speculation why 

 the life-fluid of higher animals should have so 

 vivid a hue, seeing that it is normally concealed 

 from view, and seldom or never plays any part in 

 determining the surface-colouration, excepting in 

 a blush. It is only a partial explanation to say 

 that the redness is due to haemoglobin, and that it 

 is an inherent physical characteristic of this body. 

 The reason for the red colour is quite as difficult 

 to explain as to account for the distinguishing 

 colours of gold, silver, or copper. It is no ex- 

 aggeration to say that haemoglobin is the most 

 important substance in the complex combination 

 called blood, for it is haemoglobin which absorbs 

 oxygen from air or aerated water, conveying it to 

 all tissues in need of that vital gas, receiving carbon 



( J ) There appear to be only two exceptions to this rule, viz., 

 the lancelet (Amphioxus), which is the lowest vertebrate, 

 and the transparent little fish Leptocephalus, now regarded 

 as the larval stage of the eel. 



dioxide in 'return, and finally giving up the excess 

 of this waste-product of combustion to the sur- 

 rounding medium. Haemoglobin can be artificially 

 separated from blood to form crystals, differing in 

 shape according to the animal. Usually, as in 

 man, they take the form of prismatic needles or 

 rhombic plates. It can furthermore be resolved 

 into hasmatin, a dark-brown amorphous powder, 

 and an albuminous substance called globulin. 

 Under the spectroscope it exhibits a very characte- 

 ristic absorption-spectrum('-), by means of which 

 Lankester and others have been able with absolute 

 certainty to demonstrate its presence in the blood 

 of certain invertebrates. 



The haemoglobin in the blood of vertebrates is 

 contained exclusively in little circular discs( 3 ), the red 

 corpuscles. In the few instances in which it occurs 

 in invertebrate animals, it is generally diffused in 

 the plasma, e.g. in the blood of the earthworm and 

 many other Chaetopod worms, in some leeches (the 

 Gnathobdellidii), in some Nemertine worms (e.g. 

 Polia), in the freshwater mollusc Planorbis, in a few- 

 small crustaceans (Cheirocephalus and the water-flea 

 Daphnia) and in the so-called bloodworm (the larva 

 of the midge, Chironomus). Less frequently it is 



( s ) It is interesting to note, as Prof. Church points out, that 

 haemoglobin possesses the same conspicuous absorption, 

 band in the ultra-violet as chlorophyll, although, of course, 

 the rest of the spectrum is very different. 



( 3 ) Elliptical in fishes, amphibians, reptiles, birds and in the 

 camel family. In the lampreys, however, the red corpusc'.es 

 are circular. 



