The problem of the comparative nutritive value of bread made from the various high grade white or “patents” flours and the so-called “standard” meal is of some interest. The inclusion of a considerable portion of the bran in standard bread is claimed to increase largely the nutritive value of the bread. It has been known for many years that wholemeal bread containing the bran particles was especially useful as an article of diet for persons suffering from constipation, the laxative effect being due partly to the mechanical presence of indigestible fibre, partly to the irritation of the intestinal wall by the sharp bran particles causing increased peristalsis. This effect is to some extent lost after prolonged feeding.

The bacteria which maybe included together as the Gaertner Group are of considerable importance, comprising as they do most of the bacteria found in outbreaks of food poisoning and in paratyphoid fever, while they are etiologically concerned with a number of diseases in animals both domesticated and wild.

Epizootics of various Fish-diseases due to bacteria have been described by several observers, but most of these have affected coarse fish only, such as carp, tench and perch and the bacilli, which have been described as the causative organisms, have been quite different in their characters from those constantly found in the epizootic now under consideration.

1. The red blood corpuscles of different species have definite and distinct mean lytic points.

2. The apparent tonicity of sheep serum has no relation to the mean lytic point of the red corpuscles of that individual.

3. The apparent tonicity of sheep serum is not due to its proteins but to its lipoids.

4. The residue of sheep serum, after removal of proteins and lipoids, is sufficiently alkaline to cause lysis.

In all countries which make statistical returns, attention has been directed to the large proportion of children failing to complete one year of life. Even the most highly civilised races lose in this way more than ten per cent, of their potential citizens as will appear from the data contained in the following table (Deutsche Sterbetafeln, 1910).

1. The action in vitro of normal rabbit-serum upon B. coli commune consists usually of three or more phases, the duration of which is inversely related to temperature.

2. The latent period which occurs on first mixing bacteria and serum is followed by a period of bacterial growth, which in its turn yields to a period of bactericidal action. This may remain final or may be succeeded by a second period of growth.

3. The germicidal action, both in case of normal rabbit-serum upon B. coli commune and of normal goat-serum upon B. typhosus, takes place in accordance with a logarithmic law so that death-rate remains proportional to the concentration of surviving bacteria.

The bactericidal action of serum thus falls into line with all other cases of disinfection, hitherto investigated.

4. The temperature coefficient of the bactericidal action of serum is low in comparison with that found for other germicides, being 2·84 per 10°C. rise in temperature for normal rabbit-serum and B. coli commune and 1·93 in the case of normal goat-serum and B. typhosus.

5. Growth of B. coli commune in rabbit-serum takes place logarithmically so that the concentration of living bacteria after equal intervals of time form terms of a geometrical series.

The calculated value of the generation-time is slightly greater than that obtaining in broth at the same temperature.

6. The influence of temperature upon rate of bacterial growth in serum is comparable with the effect upon growth in other media. The generation-time is decreased 2·01-fold for a rise in temperature of 10°C.

7. The separate processes of bacteinal growth and death in serum being similarly influenced by temperature, there is no support for the view that the significance of fever might be concerned with a tendency to encourage either process relative to the other.

The literature upon the presence of various ferments in milk is extremely large and dates back through many years. Up to the beginning of 1911, however, when the experiments described in this paper were undertaken, no observer had dealt with milk uncontaminated by bacteria.

(1) If a series of dilutions of an antiserum are prepared, a dilution can be selected which when mixed with an appropriate quantity of the homologous antigen forms no precipitate but nevertheless binds complement. If complement is added to such a mixture of antigen and antiserum a precipitate appears after an interval of six to twenty-four hours.

(2) By using an appropriate mixture of antigen and antiserum the amount of the precipitate can be increased, within certain limits, by increasing the amount of guinea-pig serum (complement) present in the mixture.

(3) Similar results can be obtained if an euglobulin solution prepared from guinea-pig serum is substituted for the normal guinea-pig serum.

(4) A suitable mixture of antigen and antiserum precipitates the euglobulin of guinea-pig serum in a manner which may be compared with the precipitation of euglobulin by carbon dioxide.

(5) By keeping a, precipitating mixture of antigen, antiserum and complement at a temperature of 0° C. it is possible to demonstrate that the resulting precipitate contains the mid-piece fraction of the complement in an active state.

The mid-piece fraction is not used up when it is bound by a mixture of serum with its homologous antiserum.

(6) The precipitate which results from the interaction of antigen and antiserum fixes both fractions of the complement. The mid-piece is fixed much more readily than the end-piece but it is possible to demonstrate a stage when a considerable quantity of end-piece has been bound while a small quantity of mid-piece still remains free.

(7) The results obtained in these experiments show that the fixation of the fractions of the complement by a mixture of antigen and antiserum is essentially similar to the fixation produced by suspensions of barium sulphate and similar complement fixing substances. These experiments confirm the recent work of Gengou on this subject.

(8) The particles of a precipitate probably adsorb the euglobulin of the guinea-pig serum and this adsorption of euglobulin is an essential part of the mechanism of complement fixation.

This communication contains a record of a series of experiments undertaken primarily to elucidate tbe action of complement and its fractions on a Tropin-B. typhosus system as estimated by the phagocytic index. Haemolytic experiments were also undertaken with the combined object of testing the activity of the complement-fractions and of investigating by the use of another system, certain points which arose in the course of the phagocytosis experiments. The haemolytic experiments are recorded in Part II of this communication. The term “ Tropin ” employed throughout the paper to designate the antibody in an inactivated immune serum which, in the absence of complement, is able to effect sensitisation of micro-organisms for phagocytosis, has been adopted solely for the sake of convenience and entirely without prejudice to the conception we have formed of its relation to the immune opsonin so-called, or to the general antigen-antibody reaction which, under certain conditions of experiment, involves the fixation of complement.

1. Over 450 naturally infected or wild flies (Musca domestica) were caught in Liverpool during September and the first part of October 1911 from different parts of the city. The number and kinds of bacteria carried and contained by them have been investigated.

2. The number of bacteria coming from house-flies whilst struggling in liquid may be very large, varying from 2000, the lowest figure in 5 minutes, to 350,000, the highest figure in 30 minutes. This number may be taken as a measure of their capacity to pollute liquid with their vomit or excrement, or by wallowing in it. The number of bacteria carried inside the fly is very much greater.

3. Flies caught either in insanitary or congested areas of the city carry and contain far more bacteria than those from the more sanitary, less congested or suburban areas. The number of aerobic bacteria from the former varied from 800,000 to 500,000,000 per fly, and from the latter from 21,000 to 100,000.

4. The number of intestinal bacteria as indicated by glucose bile salt fermenters is also greater in the insanitary or congested areas, the numbers varying from 10,000 to 333,000,000, than in the more sanitary areas where they carried from 100 to 10,000.

5. Pathogenic bacteria and those allied to the food poisoning group were only obtained from the congested or moderately congested areas and never from the suburban areas.

6. We have examined the morphological characters and cultural reactions of 123 strains. Among those identified were two Streptococci, and several Staphylococci and Sarcinae. 106 were small Gram negative non-spore bearing bacilli, and have been grouped as follows:

Chromogenic group. Two strains of B. pyocyaneus were isolated from a knacker's yard; for the first time, we believe, from wild flies.

Colon group. 41 colonies of this group were picked off haphazard and classified according to McConkey as follows:

B. acidi lactici type 19·5%

B. coli communis type 12·2 %

B. neapolitanus type 19·5 %

B. lactis aerogenes type 46·4 %

Salmonella group. One bacillus gave identical reactions to B. enteritidis of Gaertner except that serological tests were negative.

Morgan's infantile diarrhoea group. One identical to Morgan's No. 1, and many others closely resembling it and Morgan's Nos. 2 and 3 were obtained.

Others fall into Proteolytic, Acid lactose-sucrose (saccharose), and Miscellaneous groups.

7. Flies caught in milk shops apparently carry and contain more bacteria than those from other shops with exposed food in a similar neighbourhood. The reason of this is probably because milk when accessible, especially in the summer months, is suitable culture medium for bacteria, and the flies first inoculate the milk and later reinoculate themselves, and then more of the milk, so establishing a vicious circle.

8. On one occasion we compared the number of bacteria carried by house-flies caught in an eating house opposite the slaughter houses with the number carried by blue-bottles; the latter, as might be expected, was far larger.

9. In cities where food is plentiful flies rarely migrate from the localities in which they are bred, and consequently the number of bacteria they carry depends upon the general standard of cleanliness in that locality. This is well indicated by the fact that flies caught in a street of modern fairly high class workmens' dwellings forming a sanitary oasis (Hornby Street) in the midst of a slum area, carried far less bacteria than those caught in the adjacent neighbourhood.

10. It is clear that flies from the suburbs where infantile diarrhoea is rare carry far less bacteria than those in the city where it is common. It was, nevertheless, impossible in the time at our disposal to correlate exactly the number or varieties of bacteria carried by flies in the city with the number of cases and deaths from infantile diarrhoea in individual streets.

11. As the amount of dirt carried by flies in any particular locality, measured in terms of bacteria, bears a definite relation to the habits of the people and the state of the streets, it demonstrates the necessity of efficient municipal and domestic cleanliness, if the food of the inhabitants is to escape pollution, not only with harmless but also with occasional pathogenic bacteria.

The document, of which a translation follows, was discovered by me in the National Library at Madrid (Coll. Salazar, Vol. MSS. 3207).

I. On the distribution of the anti-neuritic substance amongst foodstuffs

1. The amounts of various raw foodstuffs that must be added to the polished rice diet to prevent symptoms of polyneuritis in pigeons for a definite period have been determined. The results indicate that the anti-neuritic body is most irregularly distributed amongst foodstuffs.

2. Pigeons fed naturally on daily rations of polished rice of 1/20th the body-weight for the first two weeks and on much smaller rations subsequently develop symptoms of polyneuritis three to four weeks after being placed on this diet and lose from 10 to 40% in weight.

3. Pigeons fed on daily rations of polished rice of from 1/11th to 1/30th the body-weight develop symptoms of polyneuritis in a much shorter time (in about 14 days). The explanation of this may be that birds fed naturally on small insufficient rations have to rely on their own tissues for supplementing the food supply and are thus able to obtain for use a larger proportion of the anti-neuritic substance distributed in the tissues than the well-fed birds. Consequently the former remain free from polyneuritis for a longer period than the latter.

4. As much as 20 gms. of raw beef are necessary daily to prevent polyneuritis in pigeons weighing about 350 gms. The small anti-neuritic value of this foodstuff indicates that the addition of flesh to a diet is not likely to be very effective in preventing beri-beri.

5. The heart-muscle of the ox greatly exceeds the voluntary muscle of the same animal in its capacity for preventing polyneuritis. This is interesting as in human beri-beri heart failure is a common symptom.

6. Sheep-brain is only about twice as efficient as beef in preventing polyneuritis. The low concentration of the anti-neuritic substance in brain suggests that the substance although essential for the integrity of the nervous tissues is not contained in them as such.

7. Although the addition of small amounts of brain to a diet of polished rice does not prevent polyneuritis, it is effective in almost entirely checking the loss in weight that ensues on this diet. Since birds fed exclusively on polished rice can only be maintained in body-weight by giving very large rations, it is concluded that there is a secondary deficiency in polished rice of substances essential for the maintenance of body-weight and that these are comparatively abundant in brain.

8. Polyneuritis is accompanied by fatty degeneration in the nervous system whether body-weight is maintained or not. This indicates that the degeneration is an effect of the deficiency in polished rice of the anti-neuritic substance and not of the secondary deficiency of substances necessary for the maintenance of body-weight.

9. The daily addition of 10 gms. of fish (hake) to the rice diet did not prevent polyneuritis and loss in weight.

10. Egg-yolk exceeds all the other foodstuffs examined of animal origin in anti-neuritic value, three grams daily added to the rice diet being sufficient to prevent polyneuritis. Its capacity for preventing this disease is not measurably altered by boiling for four minutes.

11. Dried lentils and unhusked barley are efficient anti-neuritic foodstuffs. Three and five grams respectively of these substances added daily to the rice diet are sufficient to prevent polyneuritis.

12. The loss in weight induced by daily rations of polished rice equivalent to about 1/20th the body-weight can be prevented without altering the actual quantity of food given by substituting barley for polished rice to the extent of about 30%. This loss in weight is therefore shewn to be due to a genuine deficiency in polished rice and is not the effect of underfeeding.

13. One-half a gram of dried yeast daily is quite sufficient to prevent polyneuritis and also to maintain the body-weights of birds fed on polished rice.

Yeast is more efficient in preventing this disease than any of the above foodstuffs.

14. Egg-yolk, heart-muscle, yeast, lentils and barley will be effective in the prevention of beri-beri. On account of their cheapness lentils and barley will probably be the most practicable for this purpose.

15. The relative efficiencies of the various foodstuffs in preventing polyneuritis and in maintaining the body-weights of birds fed on polished rice do not correspond. This indicates that the anti-neuritic constituent and the substances maintaining body-weight are not identical. Evidence is brought forward in the text which seems to indicate that the latter substances are not protein, fatty or lipoidal in nature.

II. On the curative properties of extracts of various foodstuffs.

1. Meat. The anti-neuritic constituent is not extracted by water and only to a small extent by ether. It is readily extracted by alcohol and after this procedure, although still insoluble in ether, is easily dissolved by water.

2. Egg-yolk. The curative constituent is present in a form readily extracted by both alcohol and ether. It is not however entirely removed by the latter solvent, since an alcoholic extract of egg-yolk which has been thoroughly exhausted with ether still possesses marked curative properties. These results indicate that a large portion of the anti-neuritic substances contained in meat and egg-yolk is not combined with the fats or free (ether-soluble) lipoids, but is possibly present in the combined lipoids, which are only extracted by alcohol.

3. Lentils. The constituent of lentils that cures polyneuritis is soluble in strong alcohol and in water, is not precipitated by basic lead acetate and is almost entirely precipitated by ammonium molybdate. There is evidence that the active substance disappears in large quantities during the latter fractionation. It is possibly destroyed by contact with alkali.

Strychnine. Strychnine does not cure polyneuritis but prolongs the lives of pigeons affected with this disease.

1. A method is described of rapidly evaporating to dryness bacterial emulsions contained in tarred flasks and from the increase of weight determining the strength of the emulsion.

The same apparatus can be used for a variety of purposes, e.g. drying serum, estimating solids in water, milk etc.

2. A very rapid method of drying bacteria smeared on a tarred piece of platinum foil, and from the dried residue preparing a vaccine is described.

3. A correlation between the number and weight of bacteria in vaccines made from agar cultures of the B. typhosus, B. coli, B. pyocyaneus, Meningococcus (Weichselbaum), Pseudo-Gonococcus, Micrococcus melitensis, B. pneumoniae Friedlander, Staphylococcus aureus and Streptococcus has been established.

4. The advantages of the gravimetric method are:

(a) That with a sensitive balance constant results are obtained.

(b) It is more rapid, and involves no strain ou the eyes.

(c) It can be applied to cultures of all bacteria growing on solid media, whether these form uniform emulsions or not, e.g. vaccines of Streptococci, Micrococcus catarrhalis, Diphtheroid organisms, B. tuberculosis, Streptothrices can be accurately standardised. Even small clumps in the vaccine considerably vitiate the results in Wright's method. The chief precaution to take in the gravimetric method is to remove the growth carefully, without breaking the surface of the medium and avoiding the condensation water.

(d) It brings into line the dosage of bacterio-proteins with that of other medical remedies.

It may be safely stated that anything which Dr A. C. Houston writes on the subject of water bacteriology is received with very great interest and respect, and his recent report on the bacteriological characters of Bacillus coli in raw, stored and filtered river water (Metropolitan Water Board, 7th Report on Research Work) is no exception to the rule. The report is of very great interest to all engaged in the study of water bacteriology, particularly in England. We who are working on this subject in a tropical country have different conditions around us, and we naturally look at things from a somewhat different standpoint, so that a brief description of our experience, and a criticism of Dr Houston's results in the light of our ideas will probably be of interest to many who are engaged in this fascinating subject.

Neisser in 1906 claimed to have discovered an organism which, when grown on lactose-agar, threw off suddenly a new strain capable of fermenting lactose. The identity of the new strain was established by Massini (1907) by many cultural and serological tests, and from that time onwards it has been generally accepted that new bacterial strains of great permanence may arise so suddenly as to justify this type of variation being named “ Mutation.”

The two processes involved in the phagocytosis of bacilli (B. typhosus) by polymorphonuclear leucocytes in the presence of a sensitising fluid, viz. (1) the sensitisation of the micro-organism, and (2) the phagocytosis of the sensitised micro-organism, have been separately investigated. A single guinea-pig end-piece acted as the sensitising fluid throughout all the experiments.

The removal of opsonin by bacillary emulsions was found to run the course of an adsorption process as evidenced by the numerical relations found to subsist between the bound and free opsonin in equilibrium.

Also the actual phagocytosis of sensitised or partially sensitised micro-organisms suspended in a neutral fluid (physiological saline) was found, on analysis by similar numerical methods, to proceed as an adsorption process.

It appears to be widely believed that the fever of infective disease is due to absorption of phyrogenetic substances liberated from dead microorganisms by a combuined process of lysis and extraction in the body of the infected subject. The diffusion of products of the action of bacterial autolytic enzymes on microorganisms after their destruction by the defensive agencies of the body is a variant on the same theme. Closely allied are the theories of protein fever, and of anaphylactic fever, in so far as they relate to the supposed possession by microorganisms, or their split products, of pyrogenetic properties. The absorption of alien protein, or of derivatives of alien protoplasm, from organisms that are dead, is, in short, the essential feature of this conception of fever production.

(1) Comfort and health can readily be maintained in dry heat where for long periods the air temperature is above that of the body.

(2) The amount of water absolutely required, and actually consumed, is very large; and this is accounted for by the necessity for neutralising, in some circumstances, the whole heat of metabolism (requiring up to 6,000 c.c.) and in addition a variable but sometimes very large amount of heat added to the body by radiation and conduction.

(3) A healthy man carries in his body a large reserve of water, this reserve being mainly stored in muscle and being so readily available that the percentage of water in the blood is not appreciably diminished even when several litres of water have been lost by sweating. If, however, it be extensively drawn on, replacement seems to occupy many hours, and this delay is an important factor, forming a strong argument against any undue or needless use of the stored water owing to restriction of drinking.

(1) A number of Dysentery bacilli of the mannite-fermenting type have been isolated from an English asylum.

(2) These bacilli may be divided into two sub-groups, (a) those that do, and (b) those that do not (1) ferment sorbite and (2) form indol in peptone beef broth in six days.

(3) Several attempts to infect a monkey with sorbite-fermenting strains were not successful.

(4) No Dysentery bacilli were found in an examination of a considerable number of flies infesting the surroundings of chronic and acute cases of bacillary dysentery.

My thanks are due to Dr H. de R. Morgan for kindly co-operation in part of this work, to Dr J. C. G. Ledingham for his valuable advice and assistance at all times, and to Dr W. F. Menzies for supplying the material for examination.

Since the publication of my paper “A Medium for Bacillus diphtheriae” (This Journal, Vol. XI. p. 271), I have had further experience of the medium and have tried various modifications.