PRESENT STATUS OF INVESTIGATION OF BEE DISEASES. 51 
ture and the A B C of Bee Culture, coupled with the excellent repu- 
tation of Mr. Cowan, made this appear convincing to American bee 
keepers. It must be remembered, however, that at that time no one 
had questioned the presence of Bacillus alvei i American foul 
brood and on finding bacilli the conclusion that they were Bacillus 
alvei was natural, even though erroneous. 
Mr. Edward Bertrand, in his book “ Conduite du Rucher,” makes 
a similar announcement, stating that he and Mr. Cowan examined 
brood described as ropy and found Bacillus alvet. 
[Mr. Dapanr: I have received a letter from Mr. Bertrand. He 
informs me that they (Mr. Cowan and himself) had examined foul 
brood, but I know from the tone of the letter that no cultures were 
made. | 
To indicate how much reliance may be placed in microscopic exami- 
nations 1n the absence of cultural tests, let me quote from Sternberg’s 
Text-book of Bacteriology, 1901 edition, pages 13 and 14. It should 
be borne in mind that this refers to all microscopic examinations of 
bacteria and not specifically to bee diseases. 
The bacteria are also classified according to their biological characters, and it 
will be necessary to consider the various modes of grouping them from different 
points of view other than that which relates to their form. This is the more 
important, inasmuch as we are not able to differentiate species by morphological 
characters alone. Thus, for example, there are among the spherical bacteria, 
or micrococci, numerous well-established species which the most expert micro- 
scopist could not differentiate by the use of the microscope alone; the same is 
true of the rod-shaped bacteria. The assumption often made by investigators 
who are not sufficiently impressed with this fact, that two micro-organisms from 
different sources, or even from the same source, are the same because stained 
preparations examined under the microscope look alike, has led to serious errors 
and to much confusion. As an example of what is meant, we may refer to the 
pus organisms. Before the introduction of Koch’s “ plate method” micrococci 
had been observed in the pus of acute abscesses. Some of these were grouped in 
chains—streptococci—and some were single, er in pairs, or in groups of four; 
but whether these were simply different modes of grouping in a single species, or 
whether the chain micrococci represented a distinct species, was not determined 
with certainty. That there were in fact four or more distinct species to be 
found in the pus of acute abscesses was not suspected until Rosenbach and 
Passet demonstrated that this is the case, and showed that not only is the 
streptococcus a distinct species, but that among the cocci not associated in 
chains there are three species which are to be distinguished from each other by 
their color when grown on the surface of a solid culture medium. One of these 
has a milk-white color, one is of a lemon-yellow color, while the third is a 
golden-yellow. 
This brings us down to the work of Doctor White. His investiga- 
tions were begun with Dr. V. A. Moore in 1902, and in January, 1903, 
a preliminary report was published. During the first year speci- 
mens of “black brood ” were examined and to the surprise of the 
investigators Bacillus alvet was found in every case. Obviously, 
