AIR SPACES IN LUNG OF CAT 467 
Recognizing that the B. N. A. is a decided advance in anatomical 
nomenclature I recommend the discarding of all previous nomenclature, 
the retention of all names given under the heading ‘Pulmo’ (B. N. A., 
p. 59) down to (and including) Ductuli alveolares, and the insertion 
then of: 
Atria 
Sacculi alveolares 
The nomenclature would thus be made uniform and the objection- 
able term ‘infundibulum’ would be discarded. The finer divisions of 
the lung would then be: 
Bronchioli 
Bronchioli respiratorii 
Ductuli alveolares 
Atria 
Sacculi alveolares 
Alveoli pulmonis 
In each instance I gave a list of the English, or English and 
German synonyms, not to recommend their general use, but that 
my English and German readers might fully understand the por- 
tion of the air space designated by the B. N. A. and myself. Not- 
withstanding my care I find some of the later authors consider 
the synonyms as a new nomenclature introduced by myself. I 
regret the misunderstanding and trust the above statement will 
make my position clear. 
The distinction between bronchioli and bronehioli respiratorii 
should be easily recognized; but Laguesse and d’Hardiviller say 
there is no sharp boundary between them. I have had no diffi- 
culty in differentiating between the muscular wall of the bron- 
chioli and the alveoli bearing bronchioli respiratorii; this is es- ° 
pecially true of longitudinal sections. Laguesse and d’Hardiviller 
state that the ‘alveolar canals’ (and, in this instance, they evi- 
dently mean bronchioli respiratorii) ‘‘may be rather long and 
may branch once or twice before reaching the acinus’’ (lobule). 
I have found this true in the case of the cat, as the illstrations 
will show, and have designated the branches as ‘a’ and ‘b’. The 
term ductulus alveolaris, as used in this study, corresponds to 
the acinous bronchiole of Laguesse and d’Hardiviller; it is situ- 
ated between the bronchiolus respiratorius and the lobule and 
is the final division of the bronchial tree before it breaks up into 
the air spaces of the lobule. 
