THE ALUMNI JOURNAL. 



"5 



Indeed the whole theory of antisepsis 

 and asepsis is based on the recognition 

 and isolation of the bacteria of septic in- 

 fection, conclusions arrived at definately 

 and positively only as a result of vivi- 

 section or the infection of the lower ani- 

 mals. 



And last but not least, the new science 

 of serum-therapy, as illustrated in the 

 use of anti-toxin in diptheria. A disease 

 hitherto more fatal and more largely dis- 

 tributed than small pox, now reduced to 

 a mortality only one half as large as ob- 

 tained previously. 



So here is then the office of that much 

 abused, much slandered art, vivisection. 

 To demonstrate and teach facts previous- 

 ly ascertained, to develop the phenomena 

 of animal life not yet understood, to aid 

 in the clear conception of diseases and 

 the discovery of means for their prevent- 

 ion and cure. 



FORMIC ALDEHYDE IN THE PRESER= 



VATION OF niLK AND ITS DETECTION 



THEREIN. 



Since a dilute solution of formic alde- 

 hyde (formalin) is being used as a milk 

 preservative, R. T. Thompson has con- 

 tributed to the Chemical News (vol. lxxl 

 247) a note on its preservative action 

 and an analytical method for its detect- 

 ion. 



The author finds that a 40% solution 

 of formalin is at least four times as effect- 

 ive as a mixture of boric acid and borax, 

 and equal to Salicylic acid; he also notes 

 that boric acid alone is much less effect- 

 ive than when used with borax. To de- 

 tect the presence of formic aldehyde in 

 milk, 100 c. c. are distilled until about 

 a fifth comes over; this is transferred to 

 a stoppered tube, and about five drops 

 of ammonio-nitrate of silver in 30 parts 

 of water, dilute ammonia being added 

 until the precipitate at first formed is 

 dissolved, care being taken to avoid an 



excess, then the whole is made up to 50 

 parts of water. The mixture of milk 

 distillate and silver solution is then al- 

 lowed to stand from 12 to 18 hours in a 

 dark place, when if formic aldehyde is 

 present, a strong black color or deposit 

 will be produced. A light brown color 

 must be disregarded, nothing short of a 

 distinct black tint being sufficient to in- 

 dicate the presence of formalin. When 

 as little as two grains of formalin per 

 gallon of milk has been used, a distinct 

 reaction is obtained. The author finds 

 that 4 or five drops of formalin added to 

 100 C.c. of milk will enable samples to 

 be kept for six weeks, which have given 

 the same results on analysis after that 

 time as were obtained from the samples 

 when fresh. Formalin should therefore 

 prove useful in preserving samples of 

 milk which may be required at a later 

 period for analytical reference. — Ph. 



fournal. 



• 



THE CATHODE RAYS. 



Two hypotheses have been proposed 

 to explain the properties of these rays. 



Some authorities think with Goldstein 

 Hertz and Lenard, that this phenomen- 

 on is due, like light to the vibrations of 

 the ether, or even that it is light with a 

 short wave length. Others, Crookes and 

 J. J. Thomson, consider that these rays 

 are formed of matter charged negatively 

 and traveling with great velocity. From 

 a *paper by Jean Perrin of the Paris 

 Academy of Science, we learn that ac- 

 cording to his experiments, the facts ob- 

 served do not easily agree with the the- 

 ory which regards the cathode rays as ul- 

 tra-violet light, on the contrary, they are 

 in harmony with the theory which re- 

 gards them as material radiation. 



Their utility in human pathology and 

 surgical diagnosis has been already fully 

 proven. 



♦ Scientific American Supplement, No. 1055, Page 16868 



