A series of 222 strains has been analysed serologically and 156 have been found to react with one or other of four sera prepared with haemolytic streptococci of scarlatinal origin.

Among the 156 strains the four chief types were distributed in the following proportions: 10 of Type I, 57 of Type II, 45 of Type III and 44 of Type IV.

The remaining 66 strains of the series have not yet been classified; though they certainly include individualistic strains, there may be other types to be defined by further analysis.

The four chief types are well defined and can generally be identified by direct agglutination. Cross-agglutination may cause confusion when suspensions are unstable, in which case resort must be made to agglutinin absorption. In addition, certain Type I strains may also agglutinate with Type III serum.

Analysis of clinical data in a series of 100 cases shows clearly that a fairly severe form of scarlatina with greater tendency to complications is often caused by infection with Type II scarlatinal streptococcus; Type II has so far been found only in association with scarlet fever.

There were nine instances where two or more members of the same family developed scarlatina; in six instances the same type was found in each patient and in three each patient yielded an unclassified strain. In one instance the strains from two members of the same family were different.

Haemolytic streptococcus colonies on fresh blood agar present three chief varieties; there are minor differences between these dependent on the amount of moisture in the medium.

There is a certain correlation between variety of colony and serological type. Type III colonies retain a soft consistency after two days' incubation, while the other types generally become tough and can be lifted from the medium as a whole.

Rough and smooth colonies with differential characters analogous to those occurring in pneumococcus cultures have not been identified. An interesting change in appearance is the production of a clear dome-shaped watery or slightly mucinous colony (3rd variety) in a culture which ordinarily forms either more or less opaque or soft coherent colonies.

There is evidence that the proportions of the four main types are likely to vary in different localities and in different outbreaks of scarlet fever in the same locality.

The importance of a reliable classification of haemolytic streptococci is discussed.

1. The development and use of a medium which has selective properties for the growth of B. typhosus and B. proteus is described.

2. The principle of the method rests (1) on the positive property of the B. typhosus of being able to reduce a sulphite to a sulphide in the presence of glucose, (2) on the inhibitory action on the growth of B. coli of a bismuth sulphite in the presence of a certain excess of sodium sulphite.

3. The media finally developed are made in the following way:

A. To 100 c.c. of a melted 3 per cent. nutrient agar are added 5 c.c. of a 20 per cent. solution of glucose, 10 c.c. of a 20 per cent. solution of sodium sulphite (anhydrous), 5 c.c. of a standard bismuth solution. After boiling for two minutes an addition is made of 1 grm. of exsiccated sodium phosphate and 1 c.c. of an 8 per cent. solution of ferrous sulphate crystals.

Medium B is the same as above with the addition of 0·5 c.c. of a 1 per cent. watery solution of brilliant green. The standard liquor bismuthi is prepared by mixing 60 grm. bismuth citrate with 50 c.c. of distilled water and then with 20 c.c. liq. ammonii sp. gr. 0·880 and finally making the volume up to 500 c.c. with distilled water.

4. On these media the B. typhosus grows readily and forms flat blackdry surface colonies. B. proteus grows on the medium in a non-spreading fashion but does not form black colonies. B. coli either fails to grow or after a period of inhibition forms brown sticky raised colonies.

5. Bismuth media were used in the examination of 31 enteric stools and in 30 instances the infecting microorganism was successfully isolated. Single examinations only were made and the material was usually 24 to 48 hours old at the time of examination.

6. Emulsions of enteric stools which as shown by the usual media contained only a dozen or so of typhoid bacilli were found by our bismuth media actually to contain several thousand.

7. The isolation from a case of typhoid fever of a proteus X 19 strain is recored.

8. As regards its growth on bismuth sulphite media B. paratyphosus B behaves more like a reducing B. coli than a B. typhosus culture. For the isolation of B. paratyphosus B a lactose bile salt brilliant green medium is described.

The following investigation into the effect of pasteurisation on the tubercle bacillus was commenced in 1923, in order to ascertain whether the temperatures used in commercial pasteurisation are at all times sufficient to destroy the virulence of the tubercle bacillus in naturally infected tuberculous milk, i.e. milk as secreted by a cow suffering from tuberculosis of the udder.

1. Examination of nine type strains of Brucella, collected from various sources, by agglutination and the absorption of agglutinin test revealed distinct serological difference between Br. abortus and Br. melitensis. Differentiation could only be made by the agglutinin-absorption test, both organisms agglutinating equally with abortus or melitensis immune sera.

2. By agglutination alone differentiation could be made between a group consisting of Br. melitensis and Br. abortus strains on the one hand and a group which included one strain labelled Br. melitensis, one labelled Br. abortus, and Br. paramelitensis.

3. The agglutinin-absorption test showed that this Br. paramelitensis group comprised two strains of closely allied paramelitensis strains, and that the Br. abortus strain could be regarded as a Br. para-abortus strain.

4. Serological investigation of eight strains of Brucella isolated from patients suffering from undulant fever in Southern Rhodesia showed that six were serologically identical with type Br. abortus and two identical with what is regarded as a Br. para-abortus strain.

5. It is suggested that the melitensis-abortus group represent the “S” normal types, whereas the paramelitensis-para-abortus group represent the “R” mutant types of organisms.

In a preliminary paper (1926) I have shown that most strains of haemolytic streptococci obtained from scarlet fever may be placed in two very definite serological groups. The strains from 119 cases were found to belong to Type I, from 57 cases to Type II, while from 34 cases the strains were un-identified. That the scarlatinal streptococci do not form one serological group has been confirmed by Griffith (1926) and by James (1926). Further, the sera and type cultures used in this investigation have been interchanged with those of Dr Griffith, and his Types I and II strains have been found to conform with the main serological types found in Aberdeen.

An examination of the literature shows that there is considerable difference of opinion on this subject. Some workers found that sera obtained from cases of scarlatina agglutinated scarlet fever streptococci to a high titre, while others believed that no agglutination could be obtained unless the sera were concentrated.

Rickets is produced in rats by feeding exclusively with cereals and yellow peas. Whereas feeding with polished rice results in typical rickets, feeding with rice-starch alone will only produce osteoporosis. This difference is not attributable to nitrogen starvation.

If oatmeal is extracted with hydrochloric acid and the extract is given in addition to the starch, the animals develop rickets. The rickets-producing factor of oatmeal must therefore be ascribed to some toxic substance. Evidence is given to show that this substance can pass through parchment-paper and that it can be precipitated with alcohol. Rickets produced by feeding with cereals can be prevented by the administration of calcium-salts, whereas phosphates have no such effect.

The British genera of blowflies, if the term be restricted to members of the Muscid subfamily Calliphorinae, are Calliphora with the two species erythrocephala Mg. and Vomitoria L., Lucilia, with several species, of which the commonest in the Manchester area are caesar L. and simulatrix Pand., and Protocalliphora, withe two species azurea. Fln. and groenlandica Ztt., of which the later alone concern us.

In his classical treatise on Contagions, Hieronymus Fracastorious of Verona has the following passage: “I recollect a singular contagion of the year 1514 which affected only oxen; it first showed itself in the district of Frioli, then gradually extended to northern Italy and thence reached our country. At first the ox went off its feed without any obvious cause, but if the herdsmen looked into the mouth a certain roughness and small pustules were noted on the palate and the whole oral cavity. It was necessary at once to isolate the infected beast from the rest of the herd, otherwise all became affected. Gradually the disease descended to the shoulders and thence to the feet, and almost all the beasts in which this happened recovered, but when it did not, they usually died” (Fracastorii, pp. 63–4). Probably, as in the parallel case of influenza, a careful search of earlier literature might show that foot-and-mouth disease had played its part before 1514. It is sufficient for my present purpose to establish that it has been recognised, very much in its actual clinical form for more than 400 years.