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 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.

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.

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.

(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.

The variously coloured patches appearing on the surface of chilled beef are caused by fungi. Amongst these, Cladosporium herbarum, producing black spots, is the only fungus that has become specially adapted for flourishing on such an unusual substratum, and may in consequence be expected to continue and even increase in quantity on its new matrix, unless stringent measures are adopted. This fungus is not pathogenic, and the only effect caused by its presence is the unsightly appearance of the meat and consequent deterioration in value. If extensive, the meat may be rendered unsaleable.

The beef is infected with the “black spot” fungus before, it is shipped, and to arrest the continuance of this infection special measures should be taken, with the object of exterminating the fungus, which in its specialised form can only occur in the vicinity of the establishment where meat is prepared for shipment.

The great reduction of the number of cases of Mediterranean or Undulant fever in the Naval and Military forces has been frequently noted since the year 1906, when the prophylactic measures recommended by the Commission of the Royal Society were put into force. Very few cases have been notified since, and in all, the means of infection has generally been easily explained.

Everyone who has been occupied with the weekly production of diphtheria toxin in quantity has been struck with the great variations which may and usually do occur in the strength of the toxin from week to week. It is indeed extraordinary as Madsen remarks (1908, p. 83) that a bacillus should for a long time give good and fairly constant results when grown in one laboratory and yet fail to do so when grown in another laboratory in a medium prepared with the greatest care according to the formula used in the first laboratory. That it is notmerely a question of medium is shown by the following experiment.A batch of bouillon was made up and inoculated in the usual way. Then half the flasks were placed in one of the two hot rooms we have here, and the other half in the other hot room. After nine days' incubation the cultures were treated as usual. Both lots were tested on the same day and it was found that while the M.L.D. of the one half was 1/150 c.cm., that of the other was 1/50 c.cm. Many and varied have been the procedures suggested for growing the diphtheria bacillus so as to obtain a highly potent filtrate and most of them have been tried in this laboratory but none can be depended upon to give a constant result. When discussing this point Dean (1907, pp. 467–468) gives the M.L.D. of a large number of toxins prepared under his direction, but they are notgiven in order as they were prepared and so one cannot get an idea as to how one batch differed from the next. I have not come across any such series in the literature of this subject and so it seemed that it would be of interest to put on record a two years' series of results in theorder in which they were obtained—more especially as a study of thisseries gave more food for thought than was anticipated.

Numerouspapers have been published on the effect of heat on diphtheria antitoxin, but there appears to be no record of a series of observations carried out at a temperature nearly that of the human body. The object of this note is to fill in this slight gap in our knowledge.

(1) Pathogenic organisms such as B. dysenteriae (type “Y”) cannot be recovered from pupae or imagines reared from larvae to which these organisms have been administered.

(2) When the larvae have been bred from disinfected ova and are subsequently fed on B. dysenteriae (type “Y”), this organism may be successfully recovered from the pupae and imagines in a small proportion of cases.

(3) Under similar conditions B. typhosus was not recovered in a single case from pupae or imagines.

(4) In those cases in which B. dysenteriae (Y) was successfully recovered from pupae, the colonies on the plate were invariably fewer than those obtained from pupae and imagines after administration to the larvae of more adaptable organisms such as “Bac. A”(Ledingham).

(5) When organisms such as “Bac. A” were administered to larvae bred from disinfected ova, or non-disinfected ova contaminated with this organism, it was in many cases possible to recover the organism from pupae and imagines.

(6) In no series of pupae examined after administration to the larvae of either B. dysenteriae or “Bac. A” was it possible to recover the organisms in every instance. A certain proportion of pupae in both cases proved sterile, so that the process of metamorphosis is undoubtedly accompanied by a considerable destruction of the bacteria present in the larval stage.

(7) The temperature at which the larvae develop (19°–25°C.) has probably an important bearing on the survival of pathogenic organisms such as “Bac. Y” of dysentery, administered in association with organisms such as “Bac. A,” in view of the fact that the latter grows far more luxuriantly at this temperature. Even when grown in broth at 37°C. (the optimum temperature for Bac. Y) together with “Bac. A,” the “Bac. Y” was found to form after two days only one quarter of the total number of bacteria present in the mixed growth.

(8) There was no evidence that the larval juices contained substances bactericidal for Bac. Y. The bacilli died more rapidly in normal saline solution.

(9) The possibility of flies becoming infected from the presence of pathogenic organisms in the breeding ground of the larvae may be considered as very remote.

1. The generation-time of B. typhosus in 1% peptone at 37°C. is 40 minutes.

2. The rate of growth of B. typhosus is greatly influenced by the concentration of peptone in nutrient medium when the peptone is below 0·4%.

3. Below 0·2% the generation-time is inversely proportional to the concentration of peptone used.

4. The addition of 0·175% of glucose to a medium containing only 0·1% of peptone lowers the generation-time by about 50% With 1·0% peptone this effect is less marked.