42 SUMMARY OF CURRENT RESEARCHES RELATING TO 



(3) of the nature of tendons ; (4) and local modifications of the myo- 

 fibrils, of the nature of -irreversible contraction phenomena following- 

 unusual functional conditions or stresses, i.e. in essence, irreversible con- 

 traction bands (Jordan and Steele). Another view, allied to the inter- 

 pretation of the discs as tendinous, is Dietrich's co-ordination mechanism 

 theory. The authors adhere to the interpretation of the discs as 

 secondary modifications of the myofibrils at certain areas characterized 

 by unusual functional conditions, probably excessive stresses. These 

 involve an inability on the part of the contraction bands to revert to the 

 relaxed condition. The myofibrils are subsequently modified chemicalJT 

 and mechanically. IMuch histological and embryological evidence is 

 submitted. 



c. General. 



Effect of Alcohol on White Mice.* — L. B. Nice found in a previous 

 series of experiments that white mice were not markedly affected when 

 given alcohol in their food. But Stockard has brought forward some 

 striking and conclusive results demonstrating that guinea-pigs are very 

 sensitive to fumes of alcohol and are decidedly injured by it. Nice,. 

 therefore, subjected mice to fumes of alcohol every day of the week,, 

 except Sunday, keeping them breathing the fumes until they became 

 intoxicated. This took about an hour at first ; after a month a certain 

 tolerance had been acquired, for it took about two hours. 



The results of the inhalation method were much the same as those 

 of the feeding experiments. The mice were not much the worse of the 

 treatment. The fecundity of the alcohol mice was greater than that of 

 the control mice. Six p.c. of the young of the male alcohol line, 6"S p.c. 

 of the double alcohol line, 9'8 p.c. of the female alcohol line, and 4 p.c. 

 of the second generation alcohol line died from lowered vitality, while 

 none of the control young died. Similar results were obtained in the 

 previous feeding experiments, except that the alcohol line had a higher 

 death-rate — ll'l p.c. in the first generation, and 12-5 p.c. in the second 

 generation. 



The growth of the young of all the alcohol lines exceeded that of 

 the controls, as in the former feeding experiments. The young of the 

 second generation alcohol line outgrew all the others. There were 

 no abortions, no stillbirths, and no monsters obtained either in the 

 inhalation or in the feeding experiments. 



A comparison with Stockard's experiments on guinea-pigs shows- 

 the danger of drawing far-reaching conclusions from data obtained on 

 a single species. It is well known in other connexions that mice are 

 very resistant in comparison with guinea-pigs. Mice are immune to 

 the toxin of the tetanus bacillus, and it is not surprising that they 

 have a considerable degree of resistance to the effects of alcohol. 



'Auditory Ossicles of Aplodontia.t — T. D. A. Cockerell has studied 

 the ear-ossicles in this genus, the only representative in the modem 

 fauna of an ancient series of Sciuromorph rodents which, in one of it& 



* Amer. Nat., li. (1917) pp. 596-607. 



t Bull. Amer. Mus. Nat. Hist., xxxv. (1916) pp. 531-2 (3 figs.). 



