106 



SCIENCE. 



[X. S. Vol. XXI. Xo. .52.5. 



allowing the collodion to deposit in a thin 

 filiu by evaporation. An anilin dye, when 

 added to the radium and collodion solutions, 

 shows the exact situation and extent of the 

 coating. 



The thin collodion covering is permeable to 

 both the alpha rays and the emanations. Such 

 coatings produce beautiful scintillations, on 

 zinc sulfid screens. Very small areas, such 

 as the tips of delicate rods, coated in the man- 

 ner described, compare very favorably in dis- 

 charging the electroscope, with 1 gram prepar- 

 ations of radium bromid of 10,000 activity 

 in glass tuhes, or with 10 milligram prepara- 

 tions of radium bromid of 1,000,000 activity 

 in thin aluminium tiibes. When air is blown 

 over the radium coatings the air carrying the 

 emanations discharges the electroscope. These 

 facts were demonstrated by the author. 



The radium coatings make it possible to 

 apply radium directly to practically every part 

 of the body. The radium thus applied would 

 be practically equivalent in radioactive effects 

 to the same amount of uncovered radium in a 

 layer of equal thinness. Any instrument can 

 be conveniently coated with radium at a de- 

 sired place by the method indicated. 



The author demonstrated a tubular appa- 

 ratus, containing an inner radium coating and 

 designed to convey radium radiations into the 

 lungs, for experiments on the destruction of 

 the tubercle bacillus. The same apparatus 

 would be useful in other connections for direct 

 treatment of diseased tissues. It was also 

 shown that the radiimi coatings are not de- 

 stroyed by sterilization. The activity of a 

 strip of celluloid with a radium coating was 

 undiminished after vigorous boiling. 



The availability of the radium coatings for 

 many kinds of biological investigation is so 

 obvious that nothing need be said here regard- 

 ing it. 



Home of Ike physical plieuomoKt of muscle 

 falifjue, with demonstration of tracinns. 

 Fkkdkric S. Lee. 



The investigation of the subject has been 

 continued by the emjjloyinent of a method by 

 which the isotonic curves of all the contractions 

 of an excised non-curarizcd muscle stimulated 



at regular intervals, are superimposed upon a 

 recording surface. The differences which were 

 previously pointed out in the mode of fatigue 

 of the muscles of the frog, the turtle and a 

 mammal, have been confirmed. Lohmann's 

 work, in which a frog's gastrocnemius on being 

 heated to a mammalian temperature shows a 

 course of fatigue similar to that of mam- 

 malian muscle, has been repeated and found 

 in general correct. But the turtle's coraco- 

 radialis profundus, similarly heated, con- 

 tinues to give its characteristic curve of 

 fatigue. 



Kaiser's method for determining the point 

 on the isotonic curve where the contractile 

 stress terminates, has been employed for the 

 frog's gastrocnemius, and it has been found 

 that as the height of the curve diminishes in 

 the course of fatigue, the contractile stress 

 terminates at progressively lower and lower 

 points. The lowering of the latter does not, 

 however, seem to keep pace with the lowering 

 of the summit of the curve. Hence the two 

 points seem to approach one another. 



A new form of float for water or alcohol 

 manometers, with demonstration: Haven 

 Emersox. I By invitation.] 

 The float consists of an aluminium cylinder 

 with very thin wall, supporting a writing arm 

 of fine aluminium wire. For manometer tub- 

 ing of nine thirty-seconds inch inside diam- 

 eter, three sixteenths or one fourth inch light 

 aluminium tubing about two and one half 

 inches long is used. In the upper end is 

 forced a solid cap of aluminium, with a small 

 hole in the center into which the wire for the 

 writing lever is driven. The lower end is 

 plugged with cork. A coating of paraffin 

 prevents leaking. The value of the float 

 consists in its cheapness, ease of construction, 

 slight inertia and delicacy. 



(Jelatin as a siihstitute for proteid in the food. 

 J. K. Mlrlix. 



In a series of experiments on dog-s, the 

 nitrogen requirement of the body was deter- 

 mined by fasting periods. Varying amounts 

 of gelatin containing from one fourth to two 

 thirds of the required nitrogen were fed, the 

 remainder of the nitrogen being supplied in 



