May 10, 1883] 



NA TURE 



47 



of the last generally contain more lutein, or sometimes tetronery- 

 thrin may be present.^ 



The presence of reduced htematin is also demonstrated in the 

 bile of the crayfish and in several pulmonate Mollusca, and its 

 respiratory and other uses discussed. 



The conclusions which these observations and others led to 

 are summed up as follows : — 



(1.) The existence of enterochlorophyll in the so-called liver, 

 or other appendages of the enteron in Invertebrates is definitely 

 established. 



(2.) This pigment occurs in greatest abundance in Mollusca, it 

 occurs less frequently in Arthropoda, and its presence in Vermes 

 is not proved. 



(3.) The pyloric cceca of starfishes contain it in great abund- 

 ance, also the intestinal appendages of Echinus, which fact 

 shows that the former function like the so-called liver of other 

 Invertebrates. 



(4.) The bile of the crayfish and that of most pulmonate Mol- 

 lusca contains haemochromogen ; in the latter it is generally 

 accompanied by enterochlorophyll, and appears to be concerned 

 more in aerial than aquatic respiration. 



(5. ) The so-called liver of Invertebrates is a pigment-producing 

 and storing organ, as well as being concerned in the preparation 

 of a digestive ferment. 



(6.) The presence of hiemochronio'en in the bile of Inverte- 

 brates is apparently determined by their mode of living, and it 

 does not appear to be distributed according to purely morpho- 

 logical considerations. 



The remainder of the paper deals with vertebrate bile pig- 

 ments, and contains some observations on abnormal urinary 

 colouring matters, mainly with regard to their spectroscopy. 

 The various bile pigments of Stadeler are first dealt with, and 

 some remarks on the bile spectra of animals follow ; here it is 

 shown that urobilin can be extracted from the liverof Salamandra 

 maculata by means of alcohol, that it is absent from reptilian 

 bile during hibernation, and that the liver of some fishes may 

 contain tetronerythrin which can be extracted from them by 

 suitable solvents. The latter fact suggests an analogous function 

 to that of the liver of Invertebrata. 



The results of the examination of a green hydrocele liquid are 

 detailed, which showed beyond doubt that biliverdin was 

 present, and since in that case its origin could be traced to blood 

 pigment, the origin of biliverdin from blood pigment is 

 demonstrated. 



The identity of stercobilin and hydrobilirubin got by the 

 action of nascent hydrogen on bilirubin is proved, and a differ- 

 ence between them and febrile urobilin shown to exist. 



The statement that the absorption-bands of sheep bile are the 

 same as those which occur in Gmelin's reaction is shown to be 

 erroneous, and a brief description of the method of isolating 

 the colouring-matter of sheep bile and the wave-lengths of its 

 different solutions given. Chlorophyll is shown to be absent. 



Under the head of urinary pigments it is shown that the feeble 

 bands described by me in a former paper in the spectrum of 

 febrile urobilin are not due to impurities but are as much part 

 of the spectrum as the band at F. Urohjematin and its differ- 

 ence from hsematoporphyrin and its pathological significance are 

 discussed. A simple method for the detection of indican in urine, 

 some remarks on uroerythrin, and on a peculiar red colouring- 

 matter in pale urine, somewhat like urrhodin, follow. The 

 deductions from this part of the paper cannot be very well given 

 in the form of conclusions, and are therefore scattered through- 

 out the paper. 



A drawing of the microscopic structure of the liver of Limax, 

 showing the enterochlorophyll within the liver cells, and maps of 

 the most important absorption spectra described, accompany the 

 paper. All readings are reduced to wave-lengths. 



Physical Society, April 28.— Prof. Clifton in the chair.— 

 A paper on colour-sensation, by Mr. H. R. Troop, was read by 

 Mr. Walter Baily, secretary. The author showed that more 

 than three colour-sensations were consistent with the theories of 

 Maxwell and Helmholtz, and explained that four primary sepa- 

 rate colour-sensations, in couples, served the theory as well as 

 three. The author gave reasons for the existence of a fifth sen- 

 sation — that of white. Mr. Stanley mentioned that his father 

 was colour-blind to green, and saw it as a brown. He consi- 

 dered partial colour-blindness very common. Mr. Lewis Wright 

 stated that he found in optical experiments a partial colour- 

 blindness from time to time, and between one of his eyes and 

 the other. He recommended the study of this partial and variable 



blindness to colours. Prof. Clifton stated that he had found 

 similar variations amongst his students, and considered that one 

 in three was unfit for delicate optical experiments. — Sir John 

 Conroy exhibited a new photometer, w hich is a modification of 

 Ritchie's, the white screens not meeting at an angle, but almost 

 meeting, and one projecting a little beyond the other, so that the 

 eye could see the outer side of one and a little of the inner side 

 of the other, both visible surfaces being illuminated by the 

 lights. The screens were inclosed in a blackened box. — Mr. 

 Walter Browne then read a paper on the causes and consequences 

 of glacier motion. After reviewing the various theories of 

 glacier motion and criticising each, the author gave reasons for 

 preferring that of Mr. Moseley, namely, expansion by heat. He 

 showed that the regelation theory now commonly accepted 

 appears inadequate, inasmuch as it does not explain the state of 

 flow at low temperatures. Mr. Stanley pointed out that Forbes 

 in his work on Norway gives expansion as a cause of glacier 

 motion. Prof. Perry referred to the experiment of Mr. 

 Bottomley (in which a wire, weighted at the ends, cuts its way 

 through a block of ice) in support of the regelation theory ; and 

 Prof. Guthrie described an experiment he had made of the same 

 kind, using a copper wire and a silk cord of the same thickness, 

 equally weighted, on the same block of ice. The wire cut through, 

 but the silk did not. Prof. Ayrton explained this on the 

 assumption that the wire conveyed heat from the air, and 

 enabled the weighted wire to lower the temperature of the ice to 

 the melting point, whereas the silk could not do so without more 

 pressure, that is weight. Mr. W. Coffin referred to the ice- 

 houses of Lake Superior, where he has seen heavy iron imple- 

 ments lying on blocks of ice at a low temperature, without 

 sinking in. Sinking took place when the sun shone on the ice. 

 Prof. G. Forbes said that below forty feet in rock variations of 

 temperature were imperceptible, and probably it was the same 

 with ice. Prof. Macleod, Mr. G. R. Griffiths, Mr. W. Baily, 

 and the President also took part in the discussion. — Prof. Fuller 

 then took the chair, and Prof. Clifton exhibited a new spectro- 

 meter of his design. In the spectrometer it is important that the 

 axis round which the prism turns and the axis round which the 

 telescope turns should not be inclined, and in the new instru- 

 ment these axes are coincident. A single cone, turned very 

 true, has the telescope piece, the circle, and prism plate fixed 

 upon it. 



Institution of Civil Engineers, April 24. — Mr. Brunlees, 

 president, in the chair. — The paper read was " Resistance on 

 Railway Curves as an Element of Danger," by Mr. John 

 Mackenzie, Assoc. M. Inst. C.E. 



Berlin 



Physiological Society, March 30. — Prof. Du Bois Reymond 

 in the chair. — Instead of the condensed milk, which, owing to 

 its large percentage of sugar, has not kept its place as a 

 food for children, a preparation of milk has lately been intro- 

 duced into the market from Switzerland, which is; protected 

 against fermentation and decomposition by previous cooking. 

 Dr. A. Baginski has chosen the relation of this new infants' 

 food to the digestive ferments as the subject of a comparative 

 investigation, which is not as yet concluded, but which has 

 elicited some physiologically interesting facts about the action 

 and occurrence of these ferments. The rennet ferment is well 

 known to act upon milk both when it is sour and when its reac- 

 tion is neutral or alkaline, but the rapidity of the curdling when 

 acted upon by the ferment is different for different tempei atures. 

 At the temperature of the room the milk curdled only after 

 twenty or thirty miuutes ; at a temperature of 20° to 25° C. the 

 curdling was already completed in five minutes ; at from 30° to 

 35° C. the curdling lasted about one minute, and it took place at 

 still higher temperatures up to 55° C. in still shorter time. 1 

 the other hand, at 60° C. and at higher temperatures the actio;* 

 of the rennet was delayed, and soon ceased altogether. In pre- 

 viously boiled milk rennet also failed to bring about curdling. 

 The rennet ferment was found not alone in the stomach, but also in 

 the small intestines and in several plants, e.g. in Carica papaya, 

 in artichokes, and in figs. In other plants it was sought for in 

 vain. Decomposition ferments had various actions upon rennet ; 

 sometimes they destroyed its action, at other times they did not ; 

 the former was particularly the case when the fluid was strongly 

 alkaline. Pepsin had no disturbing influence upon the activity 

 of the rennet, although trypsin had to a marked degree. Dr. 

 Baginski made similar observations upon the effect of decompo- 

 sition ferment, pepsin, and trypsin upon each other. — Prof. 



