as a rule, Jateral-spined egy:s, may not, as an exception, produce one 
or another teniiinal-spined egg. J 3 iologicaI processes can never be 
pressed into a mathematical formula to which there is no possible 
exception. 
Speaking of the significance of these eggs I will provisionally 
quote the opinion of HOLCOMB, who says (iQO/, p. 62): ‘ The West 
Indian infection proves that the lateral-spined eggs are not the eggs 
of unfertilized females, and some of my cases, which were under 
observation for one year or more, show only too well the persistence 
of the type of egg cannot be attributed only to young females 
Before I can respond to this argument several other points must be 
discussed; I, therefore, at this place, limit myself to quotii^ 
Holcomb’s objection, and will return to the point later. 
The habitat of the mature Bilharzia worms are the finer 
ramifications, in the first place, of the vesical and, in the second place, 
of the rectal veins. As a logical consequence of my theory, one 
ought to expect that, there, they produce terminal-spined eggs 
on y. Observation shows that the lesions actually contain such eggs 
m enormous numbers, and very often absolutely alone 
ome stray lateral-spined eggs found at the one place or the other 
not shake this rule. Even when large numbers were found 
nerous cases the fact w'ould not prove any specific nature of 
unless it were shown, either that unimpregnated females 
canr*^t places, or, that impregnated females 
oanne^t under any circunstances form lateral-spmed eggs. 
soined ^ ^^'“ales living in the portal system produce lateral- 
sLe thr* "" expel them into the surrounding blood, 
carry the themselves mobile the blood stream will 
becll a'etTLTosf '"T 
The theory t, ? i u ^ vessels whose diameter equals their own. 
latera to the log.cal Isequence that 
knoTntet i„r , " ■» ‘hat organ ts a well- 
theory rests' J'epresents another of the pillars on which mv 
"orms gr^™ up ^th (*h-h I share) the 
the pelvic organs h teacli their definite habitat in 
the weaker fem 1 ^ "’^"derings, the vigorous males carrying 
eaker females with them in the gynaecophonc canal. It .. 
