SECTIONAL TRANSACTIONS.— D. 335 



Dr. F. A. E. Crew. — Studies on the Thyroid. 



(a) The Hairless Mouse. 



A new mutation ' hairless ' in the mouse is described. This character is a recessive. 

 The coat is developed normally, but is shed when the mouse is about three weeks 

 old. "The hairless male is fecund, the hairless female is infecund and her thyroid is 

 definitely abnormal in histological structure. When the hairless female is kept at a 

 temperature of around 30° C, however, she is fecund, and matings yield offspring. 



(b) Thyroidectomy in the Hen-feathered Cock. 



Hen-feathered Campine cocks after the removal of the thyroid become cock- 

 feathered. The bearing of this fact upon the physiology and genetics of plumage 

 characters is discussed. 



Mr. D. Ward Cutler and Mr. L. M. Crump.— The Effect of Food Supply 

 on the Multiplication of Protozoa. 



The effect of both quality and quantity of food upon the organism has been the 

 subject of considerable study in many groups of animals. Among the protozoa it 

 has been shown that in the case of a holozoic ciliate, Colpidium colpoda, there is a 

 very definite relation between the number of bacteria supplied to a culture and the 

 rate of production of the Colpidia. Among the Amoebae the same relation holds good 

 in Hartmanella hyalina, and in this case it has also been shown that the variety of 

 bacterium used has a marked influence on growth and reproduction, certain varieties 

 having a high and others a low nutritive value. 



Mr. G. P. Wells. — The Action of Potassium on Contractile Tissues. 



Although very similar in their chemical properties, Sodium and Potassium have 

 widely different physiological actions. Experiments illustrating the action of 

 Potassium on the tone of muscle-preparations from Gasteropods {Helix and Aplysia) 

 and Decapod Crustaceans (Naia and Cancer) are described ; in both cases, as in 

 Mammalian plain muscle, there is augmentation of tone if Potassium is either with- 

 drawn or greatly increased above its normal concentration. Certain possible 

 mechanisms of the specific effects of Potassium are discussed. The fact that in 

 Aplysia the characteristic effects of Potassium can also be produced by the Ammonium 

 ion suggests that the secret of Potassium specificity lies in a property such as ionic 

 mobility, and excludes radioactivity from being a possible cause. 



Prof. P. Douglas Laurie. — The Position of Biology in the School 

 Curriculum. 



Some study of biology should be included as an integral part of the education of 

 every boy and girl. 



It is of first importance to consider the scope and treatment of the subject for 

 children of the 12-10-year group, the great majority of whom are preparing for 

 citizenship without thought of going through the universities. It should be regarded 

 as thoroughly bad to divorce from each other the study of animals and plants at this 

 stage. 



Biology which does not include plants fails to cover adequately the relation of the 

 living to the non-living world ; without animals it fails in its human significance as 

 a foundation for hygiene, human physiology, and social science. This has been 

 realised in other countries much more than in our own. The common fallacy that 

 animals lend themselves less readily than plants to simple physiological experiment 

 has been exploded. 



It is suggested that in girls' schools botany, now so prevalent, should be converted 

 into biology, and that botanists and zoologists should unite in claiming for biology 

 the place due to it in the time-table of boys' schools. The movement in girls' schools 

 has already begun ; it may be anticipated that the slower movement to be expected 

 in boys' schools will not be long delayed. The chief difficulty is the lack of qualified 

 teachers, particularly for boys' schools, a lack to which more than one recent Govern- 

 ment report has called attention. 



