406 TRANSACTIONS OF SECTION D. 
Amphibia.tA Hemogregarine has been met with in one species of frog 
only, Trypanosomes in several species. 
Fishes.—Trypanosomes have been found in the freshwater eel and in a 
catfish. 
5. Adaptation and Inheritance in Silkworms. 
By Professor Orro Maas. 
The experiments in the feeding of silkworms on the leaves of our well-known 
vegetable Scorzonera hispanica, tormerly undertaken by Harz, Tichomiroff, and 
others, for practical purposes, have been repeated by me on theoretical grounds, 
as well as by different methods. 
As none of the breeds cultivated by Harz’s selective method have survived, 
selection appears not to operate at the length of generations, and consequently 
the much-vexed question of the heredity of acquired characters cannot be omitted. 
General constitution, ‘ Wichsigkeit,’ plays its part as well; qualities are trans- 
ferred according to now well-known laws of heredity, especially Mendel’s, the 
breeds have to be analysed, in this regard as well, and crossings of normally 
fed with Scorzonera-fed are to be tried. 
Hence the necessity for working on a larger scale, which I began (after 
some orientating experiments in 1910 and 1911, on the possibility of feeding 
and selecting some breeds) in 1912. The same material for breeds has to be culti- 
vated in different places, to avoid local failures; different races of silkworms 
have to be tried on the same food, and different feeding on the same race 
(mulberry, Scorzonera, and half Scorzonera and half mulberry), in order to get 
a material for suitable crossings, and to produce new possibilities. c 
In accordance with Kellogg, in spite of all gradations, four main types may 
be distinguished, of which I used chiefly three (with different eggs, colours, 
and shape of cocoons and moth-pattern), designated here for convenience with 
the letters Jap., It., and T., and of these three races different grada- 
tions have been applied ; for instance, Japanese freshly imported, and Japanese 
cultivated for years in Europe; Japanese of the wild form (mandarina) ; Italians, 
whose parents had been fed by myself, 1911, with Scorzonera, and others normal 
from the sericultural institutions ; Tessin normal and with Scorzonera-fed parents, 
&e. Results of the 1912 feeding are, among others: {1) the It. and T., whose 
parents had Scorzonera, 1911, did not get well through the same treatment, but 
died out in spite of every care, in several localities, whereas the freshly imported 
Jap., It., and the normal T. sustained the new food comparatively well. (2) Still 
Scorzonera-fed in 1912 held together with mulberry-fed ones of the same race &c. 
show great differences. A much smaller percentage comes to the respective 
moultings, much longer time is required (fifty-six days instead of thirty-six), and 
there is especially a long hesitating and wandering period of the big, well-fed, 
worm, till it begins to spin. (3) Its cocoon, however, is not inferior, either in 
size, density, or strength of thread. The crossings of the various breeds show 
marked differences in their productiveness. The capacity of fertilisation (active 
and passive) of Scorzonera moths, even of first-rate cocoons, is apparently much 
inferior (this can be verified not only by general comparison, but also by trying, 
for instance, the same male with different females and vice versa); fecundity, 
judged by the number of deposited eggs in the same race, is much less ; in many 
cases the females could not fasten their eggs (though that was here not a race 
character). Also of the fertilised eggs many more decay than in normal egg- 
deposits, and of the remaining a much smaller number is able to hatch in the 
next year (v. infra). : 
All these damages are most significant, if both parents are Scorzonera-fed 
(thus a number of possibilities are at once excluded from further propagation), 
while in the case where one parent was normally fed the mating could be as 
fertile as a normal one. In 1912 all possibilities of race-crossings and treatment 
were tried (a distinction also was made if the male had Scorzonera and the 
female mulberry or vice versa), altogether over thirty, which formed the starting 
material for 1913. 
Of these egg-deposits single ones always have been selected (to work on 
‘pure lines’ for other purposes, of which T shall give an account elsewhere), 
