1008 



SCIENCE 



[N. S. Vol. XXIX. No. 756 



disease is coincident with the formation of the 

 sexual products. The highest daily mortality was 

 reached when the chicks were eleven days old. 

 One month after the beginning of the epidemic 

 394 chicks had died out of 510. The Bacterium 

 septicemicE gallinarum of Eettger was not found 

 in connection with the present epidemic. 

 Some Experiences Relevant to the Determination 



of the Bacterial Content of Milk: Chables E. 



Maeshall, Director, Michigan Agricultural 



College, East Lansing, Mich. 



It is assumed from the observations in the 

 (a) Association Studies conducted by the author 

 and Miss Farrand, in the (6) Butter Studies 

 conducted by W. S. Sayer, Otto Eahn and Miss 

 Bell Farrand and in the (c) systematic work 

 performed by Miss Zae Northrup, all in the bac- 

 teriological laboratory of the Michigan Agricul- 

 tural College, that: 



1. Milks vary in their bacterial content as to 

 both (a) numbers and (6) species. 



2. This variation is dependent upon the (a) 

 source of the milk, (6) method of milking, (c) 

 cleanliness in handling, {d) temperature main- 

 tained, (e) etc. 



3. Milks in the light of the above can not de- 

 velop their germ content {a) with the same 

 rapidity or (6) in the same relative manner, and 

 therefore can not respond alike to even ideal or 

 perfect methods of testing. 



4. Methods of testing are only incidental to the 

 real problem; they should be employed to indicate 

 and assist in control. 



5. While composition of media, means of dilu- 

 tion, time of plating, temperature for plate devel- 

 opment and other factors are highly important in 

 the execution of these tests, the most essential 

 factor at this time is uniformity of methods that 

 the variable minor discordant elements may to a 

 large extent counteract each other through the 

 accumulation of evidence. 



6. It follows that the purpose of the Committee 

 on Standard Methods of Bacterial Milk Analysis 

 is justified, even though many of its detailed 

 decisions are arbitrary and perhaps unwarranted 

 should uniformity of methods be established. 



7. However, much would be sacrificed if labora- 

 tory men forgot the real purport of such analyses 

 and used them simply to estimate the milk per se 

 instead of the conditions which are indicated by 

 such analyses. 



It is suggested that perhaps more rapid progress 

 would be made and more enduring results secured 

 were the energies of workers devoted to more 



exhaustive elemental studies which will assist in 

 the solution of some of these problems. 

 Cremating Furnace for Laboratories : Chables E. 

 Maeshall. 



It consists of an open brick chimney, lined with 

 fire brick on the inner wall, and with an air space 

 between the inner and outer walls. At the bottom 

 of the chimney are the cremating apartment, the 

 fire box and the ash pit. The essential and valu- 

 able feature of the cremating chimney is the using 

 of gas pipes for grates to support the material, 

 thus enabling the placing of a fire below. These 

 pipes are so inserted in collars communicating 

 with the air outside that a cold current of air 

 passes through when heated and passes into the 

 chimney at the inner end of the pipes which rest 

 on a ledge on the inner wall of the chimney. 



Published by the Experiment Station Report of 

 the Michigan Agricultural College for 1908. 

 Preparation of a Standard Solution of Litmus; 

 Chas. W. Bbown, Michigan Agricultural Col- 

 lege, East Lansing, Mich. 



It was found that 2.5 grams of azolitmin dis- 

 solved in one hundred cubic centimeters of dis- 

 tilled water would give a solution of such strength 

 that one cubic centimeter when added to one 

 hundred cubic centimeters of milk would give a 

 blue color of the intensity desired for litmus 

 media. With this as a measure, thirteen samples 

 of litmus were standardized, giving the numbers 

 recorded in the table. 



Grams Required 

 Sample tomakelOOc.c.of Per Cent. 



Standard Solution Insoluble 



Azolitmin 2.5 



Merck's purified 7 2.3 



Soluble litmus 8 14.5 



Litmus cubes 140 87.1 



No. 1 15 44.3 



No. 2 32 68.7 



No. 3 68 81.4 



No. 4 98 89.4 



No. 5 128 92.8 



No. 6 164 92.8 



No. 7 110 91.5 



No. 8 154 94.3 



No. 9 146 91.7 



No. 10 122 91.8 



A definite amount of the sample was weighed 

 out and dissolved in a definite volume of distilled 

 water, either by placing in an incubator at 

 37.5° C. over night or by heating in flowing steam 

 for thirty minutes. The filtrate was compared in 

 Nessler's tubes with the standard solution 



