October 13, 1904] 



NA TURE 



589 



and is fairly eflicient so far as air exchange is concerned. 

 The drawbacks are that the tongue in the face-up position 

 tends to fall back and block the passage of air through the 

 pharynx ; that there is risk of rupturing the liver ; and that 

 there is risk of breaking the ribs if the operator is heavy 

 and powerful and if the patient is advanced in years. 



These drawbacks are avoided if the patient be turned into 

 the prone position during the whole procedure. Greater 

 efficiency is thereby attained, and the risk of injury to ribs 

 or viscera is reduced to a minimum. The muscular exertion 

 required is only that needed to swing the upper part of the 

 body backwards and forwards on the hands about twelve 

 or thirteen times a minute, the operator kneeling by the 

 side of or across the patient. The pressure is gradually 

 applied and gradually released. The amount of air e.x- 

 changed by this method per minute is greater than that 

 yielded by any other which has been tried, and may even 

 exceed the ordinary rate of exchange of the individual. 



Tables showing the amount of air exchanged in the 

 various methods which have been recommended for artificial 

 respiration were shown, from which it was seen that only 

 in Howard's method and in Schafer's modification of that 

 method did the amount reach that attained in normal re- 

 spiration. Schafer's method is easy to carry out, even for 

 prolonged periods, and is sufficient for the needs of a normal 

 individual who submits himself to be respired in this manner. 

 On the other hand, in both the Sylvester and .Marshall 

 Ward methods, a normal individual is unable to refrain 

 from himself actively respiring on account of the air- 

 exchange being insufficient. 



Dr. F. W. Edridge-Green read a paper on the necessity 

 of a lantern test as the official test for colour blindness. 

 Or. Edridge-Green described two cases, both naval lieu- 

 tenants, which he had examined, in both of which the men 

 passed the wool test but failed when examined by the 

 lantern test. These were selected because both had daily 

 experience with coloured lights and not with wools. He 

 concluded, then, that because a man can sort wools correctly 

 it does not follow that he can distinguish between coloured 

 lights. In his opinion many varieties of colour blindness 

 may escape detection by the wool test. 



On Tuesday, .August 23, Prof. .\. Kossel (Heidelberg) 

 communicated the main results obtained in work conducted 

 in conjunction with Mr. H. D. Dakin on the protamines. 

 These are the simplest type of proteids. One of them, 

 salmin. when treated with boiling dilute mineral acid yields 

 only live atomic groupings, viz. urea, diamido-valerianic 

 acid, serine, monoamido-valerianic acid, and pyrollidin- 

 carboxylic acid. They had investigated the relative pro- 

 portions in which these five substances were present in 

 salmin. and had found them approximately as follows : — 

 ten molecules of diamido-valerianic acid, ten of urea, two 

 of serine, one molecule of monoamido-valerianic acid, and 

 two molecules of pyrollidincarboxylic acid. The composition 

 of clupein was found to be complicated by the presence of 

 idanine in addition. On the other hand, scrombine 

 possesses an even simpler constitution, for, in addition to 

 virea and diamido-valerianic acid, only alanine and 

 pyrollidincarbo.xylic acid were found. Sturin obtained from 

 the testes of the sturgeon presents a different constitution. 

 Two diamido-acids are present, diamido-valerianic acid and 

 diamido-caproic acid, the former being combined with urea. 

 To this complex a heterocyclic group, histidine, remains to 

 be added. 



The ordinary proteids differ mainly from the protamines 

 in an increased proportion of monoamido-acids, so that the 

 complexity of molecule is extraordinarily great. This com- 

 plexity is further increased by the addition of other groups, 

 e.g. dibasic acids such as aspartic and glutamic acids, 

 ■which are not present in the protamines. 



Prof. J. E. Johansson (Stockholm) gave an account of 

 his experiments upon the immediate effect of carbohydrates 

 upon metabolism. These experiments dealt with the rate 

 of excretion of carbonic acid following the administration 

 of various carbohydrates, and were conducted upon man 

 in a respiration chamber. He first showed that for a par- 

 ticular individual the rate of excretion was practically 

 constant if taken some hours after a meal, and that this 

 rate did not vary with differences in the previous diet nor 

 at different periods of the year. If, thf-n, an individual is 

 ^jiven a quantity of a particular carbohydrate about eight 



NO. i8r?4 VOL. 70] 



hours after a meal, the amount of increase in CO, e.xcreted 

 is to be assigned to the food given. He showed in this way 

 that an increase of CO, followed the administration of 

 glucose, saccharose, or levulose, and that this increase, 

 which amounted on the whole to from 8 per cent, to 20 per 

 cent, of the total carbon given, began within the first half 

 hour and lasted from two to three hours. The increase 

 persisted longer after saccharose or levulose than after 

 dextrose, and the total amount was greater. He further 

 showed that the amount of the CO, surplus was in propor- 

 tion to the amount of carbohydrate given if this did not 

 exceed 150 grams. The effect of a dose of sugar was greatly 

 influenced by the previous state of nutrition of the person 

 experimented upon. Thus, after a fasting period of forty 

 hours, the amount of carbon retained was much greater 

 than after a ten hours' period. A further point of interest 

 was that the amount and rate of destruction of the various 

 sugars were not influenced by the performance of work. 

 The two effects were additive, and did not interfere with 

 one another. 



Mr. P. P. Laidlaw gave the results of some observations 

 on blood pigments. The iron in haemochromogen is un- 

 stable to dilute acids a fact which shows that hEemato- 

 porphyrin is present in the haematin molecule. This was 

 absolutely proved by the artificial formation of haemo- 

 chromogen by warming iron free haematoporphyrin in an 

 ammoniacal solution to which Stokes's fluid was added 

 from time to time, when on repeatedly reducing the mixture 

 for an hour or so haemochromogen was formed. The 

 method of synthesis renders it probable that hajmatin is a 

 combination of two haematoporphyrin groups with one of 

 iron. Turacin also may be synthesised from haemato- 

 porphyrin by boiling with cuprammonium solutions. 



Dr. F. C. Hopkins wished to lay stress on a further point 

 which had not, perhaps, been brought out very clearly in 

 -Mr. Laidlaw's paper. It had been found that if reduced 

 haemoglobin was treated with a mineral acid, the decom- 

 position went as far as the production of hEematoporphyrin, 

 whereas, when the same h;emoglobin was converted into 

 oxyhemoglobin and then treated with acid, hajmatin only 

 was produced. From this it was clear that a very funda- 

 mental part was played by the iron in the conversion of 

 hemoglobin into oxyhsemoglobin. 



Prof. k. B. Macallum (Toronto) read a paper on the 

 distribution of potassium in animal and vegetable cells. 

 \ solution of the double nitrite of sodium and cobalt gives 

 a yellow precipitate with a potassium salt. If, therefore, 

 thin pieces of the tissue to be examined be treated with 

 this solution, and the excess of the reagent be washed away 

 with ice-cold water, the position of the potassium in the 

 cells is indicated by the presence of the yellow precipitate. 

 Its localisation may be rendered more obvious by convert- 

 ing the yellow precipitate into a black one by further treat- 

 ment with ammonium sulphide, which precipitates the 

 cobalt as a black sulphide. In this way is was found that 

 potassium is never diffused through the cell. It is more 

 abundant in vegetable than in animal protoplasm, and the 

 nucleus is always absolutely free from it. Only one tissue 

 element was found absolutely free from it, viz. the nerve 

 cell and the axis cylinder. .\ll dead and inert material in 

 a living tissue becomes charged with potassium. This is 

 especiailv the case with intercellular material. 



Dr. W. B. Hardy remarked on the difficulties of deter- 

 mining the distribution of a soluble substance in so small 

 a structure as a cell, for diffusion may be relatively rapid, 

 and thus the results obtained might be very misleading. 



Prof. Brodie suggested that the reason why the nucleus 

 never contained any of the precipitate could be readily ex- 

 plained on the assumption that the nuclear membrane was 

 impermeable to the cobalt salt. This, too, would explain 

 the fact pointed out by Prof. Macallum that in many 

 instances the precipitate was found accumulated immediately 

 around the nucleus, for if the nuclear membrane were 

 impermeable to the cobalt salt but permeable to a potassium 

 salt, the latter as it diffused out would be precipitated 

 at once by the excess of cobalt salt present in the surround- 

 ing protoplasm. 



Prof. W. O. Atwater described his investigations on the 

 nutrition of man at a joint meeting with the section of 

 economics. .\n abstract of the paper will appear in another 

 issue of Natcri;. 



