April 6, 191 1] 



NATURE 



199 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, March 30.— Sir Archibald Geikie, K.C.B., 

 president, in the chair. — Captain A. G. McKendrick : 



The chemical dynamics of serum reactions, (i) Ambo- 

 ceptor and complement are opposed in their action on the 

 cell, with the proviso that the fc~mer acts as a catalyst 

 to the latter. (2) Complement action is lytic ; ambo- 

 ceptoral action is primarily polymerising, or, as the case 

 may be, agglutinative, and secondarily catalytic to com- 

 plement. (3) The relation of these substances is expressed 

 by the law of mass action, in the form 



at c\cz J \^ ) 

 (4) When the substance acted upon is in sufficient quantity 

 this expression describes all serum reactions, viz. haemo- 

 lysis, bacteriolysis, opsonin and stimulin reactions, 

 agglutination, precipitation, and toxin action. (5) Toxins 

 are compound, and consist of amboceptor and complement. 

 — G. J. Burch : Preliminary note on a method of measur- 

 ing colour-sensations by intermittent light, with descrip- 

 tion of an unfinished apparatus for the purpose. Briefly, 

 the new method of measuring colour-sensations is as 

 follows :- — A series of flashes of monochromatic light pro- 

 duce by a real induction a condition of colour-blindness in 

 a small area of the field of view, which they surround, but 

 do not invade. This small area is occupied, also in flashes 

 properly timed and proportioned, by the part of the spec- 

 trum under examination. The colour corresponding to 

 that of the monochromatic flashes is, as it were, wiped 

 out of it, and the observer sees the boundaries of the 

 underlying colour-sensations so long as the flashes succeed 

 one another at the proper rate. — Dr. E. W. Ainley 

 Walker : Variation and adaptation in bacteria, illustrated 

 by observations upon streptococci ; with special reference 

 to the value of fermentation tests as applied to these 

 irganisms. Numerous attempts have been made to 

 fliff'rentiate and to identify varieties of bacteria by means 

 ■ ' I 'mical reactions produced by them in special culture 

 One of the most interesting of these attempts was 

 uiciL made by Gordon to prove the existence of definite 

 ieties among streptococci by the use of certain test 

 ia. Gordon and those who followed him believe that 

 sy can thus subdivide the streptococci into a number of 

 d and independent varieties, and classify them into 

 at Andre wes and Horder have spoken of as " provisional 

 ies. " Their conclusions, however, could only be 

 epted were it proved beyond question that the reactions 

 3n which they rely are stable in character and exhibit 

 :on-.tancy. In the present communication evidence is 

 d from an extended examination of particular strains 

 reptococci that the reactions concerned are by no 

 - constant. Under the conditions of ordinary cultiva- 

 :n agar jelly, and still more under culture in the 

 «ivironment supplied by special media, particular strains 

 streptococci are shown to exhibit wide variations in 

 r reactions to Gordon's test media. Thus it occurs 

 t strains which are at one time totally different in their 

 it reactions may at another time be found to be identical, 

 urther, it appears that after suitable manipulation par- 

 icular strains may be made to assume the characters 

 ■' of one, now of another, of the types supposed to be 

 ntiated by Gordon's tests. The conclusion drawn is 

 — no evidence exists of any fixed or specific differences 

 ■ng streptococci pathogenic for man, but that the 

 ences observed are due to merely temporary and 

 lal variations in the metabolism of these micro- 

 nisms, which thus readily adapt themselves to changed 

 ronment. Accordingly it is quite possible that suitably 

 ted tests may be made to afford some valuable indica- 

 as to the probable habitat or recent environment of 

 my given strain of streptococci. — W. Bateson and R. C. 

 •unnott : The interrelations of genetic factors. In the 

 pea it was early found that the distribution of 

 ; among the gametes of plants heterozygous for 

 than one pair was liable to disturbances of two 

 , known as coupling and repulsion (" spurious allelo- 

 ism "). Coupling affects the factors B, blue, and L, 

 iroblem, in such a way that the gametic system is 

 7 BL : I BZ : I bL : 7 b/. 



XO. 2162, \'nT,. Sh; 



Other factors may be coupled in systems 15 : i : i : 15 ; 

 63 : I : I : 63 ; 127 : i : i : 127 ; and presumably other 

 systems of numbers similarly related will be discovered. 

 Repulsion was first seen in the case of B, blue, and E, 

 erect standard, acting in such a way that the gametes are 

 all either Be or 6E. Such repv.lsion has since been recog- 

 nised elsewhere both in plants and animals, affecting 

 especially the factor for femalemes. Subsequently it was 

 observed (sweet pea) that two factors, viz. that for dark 

 axil and that for fertile anthers, which had previously 

 been found coupled together, might in another family 

 repel each other. As the result of a long series of experi- 

 ments, it has been established that if A and B be two 

 factors liable to such disturbances, the Fj from AbxaB 

 (or reciprocal) shows repulsion between A and B, but the 

 Fj from MbxAB (or reciprocal) shows coupling between 

 A and B. Two kinds of heterozygote can therefore be 

 recognised, which may be represented as Ab.aB and 

 a&.AB. The first, on segregation, makes two types of 

 germ-cell Ab and aB ; the second makes four, AB, Ab, 

 aB, and ab, with ah and AB represented in one of the 

 numbers 7, 15, &c. The polarity of the zygote-cell must 

 therefore be influenced by the way in which the factor? 

 come into it, and presumably by the positions which they 

 occupy. The triple system, B, L, E, in the sweet pea 

 has only been partially investigated, but it is known that 

 EbZxeBL gives B and L coupled, with repulsion between 

 B and E, not between B and L. An order of precedence 

 between factors must thus be recognised, 'which possibly is 

 that of the system of coupling to which they are subject. 

 — Philippe do Vilmorin and W. Bateson : A case of 

 gametic coupling in Pisum. A variety of culinary pea 

 has for some time been grown at Verri^res-le-Buisson 

 having leaflets in place of the ordinary tendrils ; this con- 

 dition is recessive to the normal. The variety has wrinkled 

 seeds. Crossed with a round-seeded normal pea, F, 

 showed coupling between the factor for tendrils (T) and 

 the factor for round seeds (R), the coupling being accord- 

 ing to the system 



63 RT : I Rt : I rT : 63 ri. 

 Coupling has not previously been observed in Pisum. 

 Owing to the fact that the seed-characters are not quite 

 sharp, the nature of the starch was determined micro- 

 scopically for each seed before it was sown. This work 

 was carried out on a large scale by Miss C. Pellew at the 

 John Innes Horticultural Institution. — R. P. Gregory : 

 Gametic coupling and repulsion in Primula sinensis. In 

 P. sinensis the short style is dominant to the long style, 

 and the magenta colour of the flowers is dominant to the 

 red colour. A series of experiments was made in which 

 a short-styled race having red flowers was mated with 

 various long-styled plants carrying the magenta-factor. 

 It was found that in the gametogenesis of the hybrid so 

 produced complete repulsion took place between the factor 

 for short style and that for magenta colour. Subsequently 

 another series of experiments was made in which short- 

 styled plants carrying the magenta-factor were mated with 

 long-styled reds. It was found that when the cross was 

 made in this way partial coupling occurred between the 

 factors for the two dominant characters. 



Royal Microscopical Society, March 15.— Mr. H. G 

 Plimmer, F.R.S., president, in the chair.— Dr. Ralph 

 Vincent : Some photomicrographs illustrating the morph- 

 ology of the organisms concerned in the production of 

 acute intestinal toxaemia in infants. These included 

 jB. subtilis, B. mesentericus " No. 7," B. m. vulgatus, 

 and B. proteus vulgaris. The photographs showed the 

 organisms stained, unstained, and during life. Photo- 

 graphs were also shown of the Streptococcus lacticus, the 

 Bacillus acidi lactici, and the B. bitlgaricus.—E. M. 

 Nelson : A new piece of apparatus. This consisted of 

 an objective mount fitted with an iris diaphragm, in which 

 the iris was just clear of the back lens, and its move- 

 ment was controlled by a collar adjustment. The 

 apparatus would no doubt be of great value to workers 

 who employ dark ground for viewing bacteria, &c., as 

 in many instances, owing to defects in the dark-ground 

 illuminator, it was not possible to obtain a dark field 

 when the objective had a wide angle. This fault was 

 remedied by stopping down the aperture of the objective 

 by means of the diaphragm. — E. M. Nelson : New objec- 



