938 SUMMARY OF CURRENT RESEARCHES RELATING TO 



He kept dilutions of blood in drinking water at the ordinary tempera- 

 ture, and others in saline solution at 37°. At the end of a year in the one 

 case, and of three months in the other, he placed the dilutions in a 

 temperature of 52°. By the end of 24 hours both dilutions had gone in 

 for almost normal heterogenesis. 



7- Greneral.* 

 Phosphorescence.^ — On this subject, Dr. C. F, W. Krukenberg reviews 

 the literature up to the present time, referring to Ehrenberg, Milne- 

 Edwards, Panceri, Pfliiger, and other investigators. He then gives in 

 detail, and at considerable length, the results of his own recent experiments 

 and observations in three special directions. The first and second of these 

 are the cases of Pteroides griseum, and Agaricus (JJrepidotus) olearius. The 

 third deals with the luminosity of the Eed Sea, and includes some very 

 graphic descriptions of phenomena observed. The experiments, which are 

 described at length and also given together in tabular form, consisted 

 principally in watching the light-producing organisms in very widely 

 varied circumstances as to medium and temperature, and also in treating 

 them with various anaesthetics and other chemical reagents. 



,Dr. Krukenberg emphasizes as the most general and important conclu- 

 sion from the investigations, and that likely to afford most guidance in 

 future research, that, in both animals and plants, whenever phosphorescence 

 is truly present, it is caused by certain vital processes being applied to the 

 production of light in a manner exactly parallel to those in which heat and 

 electricity are produced in living beings. 



Function of Otoliths. | — Prof. T. W. Engelmann made some observa- 

 tions on the functions of the so-called otoliths in the sensory bodiss of 

 Ctenophores previous to the appearance of Dr. Delage's paper. He thinks 

 what he has seen confirms the views of the French naturalist, and hopes 

 that the investigation will be carried further. The author regards the 

 so-called otoliths which are placed at the aboral pole of the body of Cteno- 

 phores as an apparatus for preserving the equilibrium of the body. After 

 a reference to the discoveries of Chun, he concludes that there is no reason 

 for adhering to the old view that the bodies in question have any auditory 

 function, and he thinks it clear that the object of the otolith is, by means 

 of the ctenophoral plates, to keep the primary axis of the body in its normal 

 upright position. When this axis is vertical, the otolith presses with equal 

 force on the four pinnate bands which extend up to it ; if the axis inclines 

 at all it presses more strongly on the corresponding JDand, and less on the 

 others. This pressure is, by means of the cellular cords connected with 

 the band, which are nervous in function, conveyed to the ctenophoral plates, 

 and thus a compensating movement of the body is brought about, and the 

 body returns to its normal vertical condition. We have here a reflex process 

 of the most elementary kind — a process of regulation in which it is not 

 necessary for either conscious sensation or will to take any part, but which 

 may be altogether mechanical. 



Eeference is made to a number of illustrative and instructive facts, 

 such as the very general presence of otoliths in freely moving animals, 

 their absence in many fixed or slowly creeping forms, and their loss in 

 fixed forms which have large otoliths in their freely moving early stages; 

 in many cases (MoUusca) they are imbedded in soft inelastic tissue which. 



* This section is limited to papers -which, while relating to Vertebrata, have a 

 direct or indirect bearing on Invertebrata also. 



t Vergleichend-physiologische Studien, iv. (1887) pp. 77-142. 

 J Zool. Anzeig., x. (1887) pp. 439-44. 



