Extracts of green peas stimulate penicillin formation by Penicillium notatum, and fractions have been prepared by treating the juice with ethanol to find the constituents present which have a stimulating action. The mould has been grown as a surface culture on a basal medium containing NaNO3, KH2PO4, MgSO4, NaCl and lactose to which the various fractions have been added. One chemically complex fraction containing a large number of amino acids (demonstrated by paper partition chromatography and estimated micro-biologically), carbohydrates and mineral matter (containing a number of trace elements) gives high yields of penicillin. The types of penicillin produced on this medium have been determined by micro-chromatography.

Chemically defined media have been formulated, and information has been obtained on the sources of carbon and nitrogen that permit growth and penicillin formation.

The amounts of carbohydrate and salts in the medium influence the formation of penicillin. Excess of carbohydrates such as glucose cause an increase in growth of the mould and a decrease in the production of penicillin.

The significance of the results in relation to the formation of penicillin is discussed.

The Golgi material of the neurones of the central nervous system of normal fowl and of birds affected with spontaneous cases of Neurolymphomatosis gallinarum (fowl paralysis) is described. Material was prepared according to the methods of Kolatchev and of Aoyama. The Golgi material of normal pyramidal cells of the cerebral cortex, the Purkinje cells of the cerebellum, the multipolar cells of the spinal cord, and the cells of the spinal ganglia, is present as rods, irregular bodies and filaments. Compact net-like Golgi material is present in the small cells of the spinal ganglia.

In the neurones of fowl affected with Neurolymphomatosis gallinarum the Golgi material undergoes hypertrophy, followed by clustering of the Golgi elements and fragmentation. The intensity of the morphological changes and the number of neurones affected in a particular region of the central nervous system varies considerably, except in the spinal ganglia where all the cells examined exhibited marked changes. It was not possible to determine whether the changes were primary or secondary in nature. The literature of the subject is discussed.

In the year 1815 an anonymous article appeared in Thomas Thomson's Annals of Philosophy (1) entitled “On the Relation between the Specific Gravities of Bodies in their Gaseous State and the Weights of their Atoms “. Its introductory paragraph illustrates the hesitancy of the writer in its exposition: “The author of the following essay submits it to the public with the greatest diffidence; for although he has taken the utmost pains to arrive at the truth, yet he has not that confidence in his abilities as an experimentalist as to induce him to dictate to others far superior to himself in chemical acquirements and fame. He trusts, however, that its importance will be seen, and that some one will undertake to examine it, and thus verify or refute its conclusions. If these should be proved erroneous, still new facts may be brought to light, or old ones better established, by the investigation; but if they should be verified, a new and interesting light will be thrown upon the whole science of chemistry.”

The genetical studies on ring-chromosomes in Drosophila show that there is no interlocking of chromatids at mitosis.

Dicentric ring-chromosomes formed at meiosis on being pulled apart do not become broken with subsequent reunion of the broken ends. This may be due to the failure of these chromosomes either to rejoin or to become broken at all.

The results make it probable that there is a gene or genes located in one of chromocentral regions of the X-chromosome of Drosophila, probably in the region at the distal end, which has a function in ensuring the orderly segregation of the chromatids in the early cleavage stages of the fertilised eggs. Hence the absence of this chromosome region results in a tendency to gynandromorphism.

Results indicate the incorrectness of the view that the inviable zygotes and the patroclinous males found in the ring-chromosome stock arise from different kinds of eggs (single cross-over and progressive double cross-over respectively, as proposed by L. V. Morgan). Both arise from eggs that have for any reason failed to receive a monocentric X-chromosome. This result occurs in all cases of digressive double crossing-over and in half the cases of progressive double crossing-over. Such virtually X-less eggs, when fertilised by an X-bearing sperm, form patroclinous males, and when fertilised by a Y-bearing sperm, form inviable zygotes. The classes thus found are therefore equal in number.

The common strain A of the blight fungus (Phytophthora infestans) and two new strains, B and C, have been employed in testing potato varieties and seedling progenies, bred from the wild species S. demissum, for resistance to the disease. The reactions of seedlings to infection with strain C are compared with those of strains A and B. The C strain is shown to be more virulent than A, since it attacks some A resistant as well as all A susceptible plants. Likewise the B strain is more virulent than A. The difference between the pathogenicity of strains B and C, however, is not one of degree of virulence; one plant may be B resistant-C susceptible, while another may be B susceptible-C resistant. This difference is essentially of a qualitative nature. Resistance to these strains, which is manifested by the hypersensitive condition of the plant's cells, is produced in the presence of three major independent genes, Re, Rb and Rbc, which confer resistance to strains A and C, A and B, and A, B and C respectively. Segregations in each case are similar in type, and are characterised by an excess of recessive individuals.

The ciliary feeding mechanism of Amphioxus (Branchiostoma bermudœ) is dependent for its continued effectiveness on the cleaning action of a powerful current of water produced by movements of the floor of the atrium. As ciliary feeding progresses, the buccal cirri become heavily choked with particles of detritus, and the feeding current entering the pharynx is thereby reduced. When this occurs, the atrial floor is violently raised and lowered, and water is pumped in and out of the atrium by way of the pharynx and oral hood, dislodging the accumulated particles from the buccal cirri. As is to be expected, the atriopore is capable of being closed during this process.

The branchial apparatus of Lampetra fluviatilis has been studied to find out whether the inspiratory movement is brought about by muscular contraction. Differences between existing accounts of the anatomy are pointed out, and a description is given of diagonal muscles which span re-entrant curves of the gill bars. Extirpation and stimulation experiments provide evidence that none of the available muscle groups can have an inspiratory function. The pressure changes in the gill sac indicate that the momentum of the water-stream in forceful expiration leaves a region of low pressure which initiates the inspiratory flow.