472 



APPENDIX 





of the two capillary tubes and take average. The square of this figure gives 

 number of units of pepsin in the i to 16 dilution of gastric juice and when multi- 

 plied by 1 6 the number of units in i c.c. of gastric juice. Normal variation is 

 8 to 100 units. 



G CHEMICAL EXAMINATION OF DUODENAL JUICE 



The general discussion of the subject of the examination of the duodenal juice is 

 taken up in Part IV. As stated there the lipase tests are rather unreliable so only 

 tests for amylase (amylopsin) and protease (trypsin), as recommended by Myers 

 and Fine are given. 



Wohlgemuth Method for Amylase. Place 5 c.c. of i% soluble starch solution in 

 each of six small test-tubes. Tube I serves as a control, and to each of the other five 

 tubes add 0.05, o.i, 0.25, 0.5 and i.o c.c. of the duodenal juice diluted one half with 

 distilled water. 



Place in 37C. incubator for one-half hour, add cold water to almost fill the tubes 

 and then several drops of N/io iodine. The positive tube will show an entire ab- 

 sence of blue color. The amylase strength is represented by the number of cubic 

 centimeters of starch solution i c.c. of undiluted juice can digest. If i c.c. of un- 

 diluted duodenal juice digests 5 c.c. of starch solution the amylase strength is 5; if 

 o.i, 50. The average normal is about 50. 



Gross Casein Method for Trypsin. Put in each of six test-tubes 5 c.c. of o.i % solu- 

 tion of casein in o.i % sodium carbonate solution and add to each one, except tube I, 

 which serves as control, the same amount of diluted duodenal juice as given above 

 for amylase. Incubate for fifteen minutes at 38C. and acidify with a few drops of 

 dilute acetic acid. The activity is calculated as for amylase and is normally from 

 4 to 10. White makes a i% dilution of the duodenal fluid with water and puts 10 

 c.c. of 0.1% casein solution in each tube. The tube with o.i c.c. of diluted fluid 

 would therefore be a i to 10,000 dilution and that with i c.c. a i to 1,000. Nor- 

 mally the i to 10,000 tube remains cloudy. Clouding of the i to 1,000 tube would 

 show marked lowering of tryspin. 



H DISINFECTANTS AND INSECTICIDES 



By disinfection is meant the destruction of injurious bacteria. 



Sterilization is where all living things are destroyed. 



Germicides are substances which kill bacteria while antiseptics are those which 

 are inimical to the growth of bacteria. 



Formalin is antiseptic in 1-50,000 dilution but germicidal only in 1-20. 



Deodorants may or may not be antiseptic or germicidal. An insecticide may 

 or may not be a germicide and vice versa. 



In disinfection we must consider 



(1) Strength of solution. It must always be kept in mind that the strength of 

 a germicide solution when added to an equal amount of material to be disinfected 

 is reduced in strength one-half. Thus i pint of a 5%'comp. cresol solution added to 

 i pint of faecal material has only a 2^% disinfecting effect. 



(2) Time of application. A common mistake is to consider a few minutes as suffi- 

 cient for contact of germ-containing material with the disinfectant. In the faeces- 



