32 HYDROCYANIC-ACID GAS FUMIGATION IN CALIFORNIA. 
AN IMPROVED SYSTEM OF FUMIGATION. 
After becoming acquainted with the chaotic condition of the fumi- 
gation practice as it existed at the commencement of this investigation; 
it was very evident that some system should be perfected which 
would entirely eliminate the guess features and provide for a calcu- 
lation of the dosage based directly on the size of the tree. As the 
result of extended observation, experimentation, and devising, a 
system of fumigation having decided advantages over the old method 
was introduced into California during the month of July, 1908. This 
system is by no means original, but is largely the result of utilizing, 
correcting, correlating, systematizing, and making entirety practical 
the best methods and ideas which either had been in practice or had 
been suggested in the State before this investigation was begun. The 
method of procedure was copied largely after that of the San Ber- 
nardino County outfits, while the method of calculating the dosage 
was suggested by Prof. Woodworth, of the University of California, 
and made practical by the adoption of the Morrill method of marking 
tents. A method quite similar in general features to the California 
improved system was introduced into Florida by Dr. A. W. Morrill, 
during the winter of 1907-8. Each of these systems was in the process 
of evolution at the same time, yet almost entirely independent of 
each other. To Dr. Morrill, however, greatest credit is probably due 
for the present advance in procedure, as the inventing of his method 
of marking tents was the turning point between impractical and 
practical scientific field calculations. 
The tents should be marked after the Morrill method described on 
pages 29-30. Only three parallel lines are used, the crossline being not 
only unnecessary but a disadvantage in practical work. This sup- 
plies an easy and rapid means of determining the distance over the 
top of the tree. The distance around the tented tree can be measured 
accurately by pacing if this is done in a careful manner. Experience 
with men on the outfit used in this investigation as well as on some 
of the practical outfits which first adopted the improved system 
demonstrated that after some practice in pacing around tents some 
men could so regulate their pace as to be sufficiently accurate for 
practical purposes. This resulted in at first advising the method of 
pacing to secure this distance. The broad adoption of this improved 
system, as well as the frequent changes that take place in the personnel 
of a crew, resulted in the pacing being assigned to various types of 
men, some of whom have been known to be hasty and careless. 
Another discouraging feature is that the tents are very often not 
properly kicked in around the bottom of the tree, which interferes 
with accurate pacing. To eliminate the possibility of irregularity 
due to the above causes it is now advised that pacing be discontinued 
