ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 827 



composition might answer equally well, except that the eyes of some 

 invertebrates may be more susceptible to rays of light of a certain 

 wave-length than our own, especially as Sir John Lubbock has shown 

 that ants perceive the ultra-violet rays of the spectrum which are 

 invisible to us. It may possibly be the persistence of a pigment 

 which was once useful in a remote ancestor in some cases, perhaps at 

 a time when the atmosphere contained much more carbon dioxide than 

 at present. Or again, it may be of use in absorbing the chemically 

 active rays of the spectrum when occurring on the surface of an 

 animal, especially as Zimiriazeff had shown that Langley's observa- 

 tions with the bolometer have proved that the point of maximum 

 energy of the solar spectrum corresponds with the principal chloro- 

 phyll band between B and C. In the case of enterochlorophyll this 

 colouring matter may be of use in furnishing material for the con- 

 struction of other colouring matters, especially as this body and 

 hasmochromogen exist side by side in the bile of some moUusks ; and 

 in the bile of the sheep and ox a body exists which fluoresces red 

 and resembles chlorophyll closely, but possesses at the same time 

 some properties which show that it is a haemoglobin derivative, as 

 proved by the writer. The conclusions which have been arrived 

 at gave support to the view which Prof. Lankester has maintained, 

 namely, that chlorophyll may occur quite independently of the 

 presence of parasitic algte, as in Spongilla and Hydra, and that 

 it is in some cases produced synthetically by and in the bodies of 

 animals. 



Klein's * Elements of Histology.' * — The student of the elements 

 of histology should have his attention directed to Dr. Klein's little 

 work, in which he will find a clear account of the leading facts of the 

 science, illustrated by a number of excellent woodcuts. Most of these 

 are taken either from the well-known figures prepared by the author 

 for Klein and Noble's ' Atlas of Histology ' or the ' Handbook for the 

 Physiological Laboratory,' which was edited by Prof. Burden San- 

 derson, while a few are new, or are taken from well-known writers, 

 such as Frey or Schultze. 



B. INVERTEBRATA. 



Colouring Matters of Bile.f — C. A. MacMunn is led by his 

 observations to dispute a generally accepted view that the liver of 

 Invertebrates is nothing more than a pancreas in function ; the most 

 striking outcome would seem to be the discovery of the wide dis- 

 tribution of a colouring matter, which is beyond doubt a chlorophyll 

 pigment ; this it is proposed to call enterochlorophyll. The author 

 has chiefly relied on the evidence afforded by the spectroscope, for, 

 as he points out, it is useless to expect that the chlorophyll in the 

 state in which it occurs should be capable of developing oxygen 

 in the presence of sunlight in the livers of Mollusca, or in the pyloric 



* E. Klein, ' Elements of Histology,' 8vo, London, 1883, 352 pp. and 181 figs, 

 t Proc. Roy. Soc, xsxv. (1883) pp. 370-403. 



3 K 2 



