PEDIGREE INHERITANCE. 
417 
so on. The biotypes are so far constant, that taken altogether, they adapt 
themselves to the limits of t^ie phænotype ; the phænotype being, however, 
variable, its changing effects also the changing of the bio types: in this 
way, the constants adapt themselves to the variable, and the categories, 
consequently, pass into each other. 
In-breeding and Cross-breeding . — Through in-breeding, as certainly 
every breeder has experienced, without employing selection, both advan¬ 
tageous and disadvantageous properties will be equally fixed. To decide 
the principal difference between in-breeding and cross-breeding, I carried 
out some parallel experiments, in which I employed on the one hand, spe¬ 
cimens which were closely blood-related, and on the other hand, speci¬ 
mens with similar properties but no blood-relationship between them, the 
properties of the ancestry being in all the cases also kept in view, I was 
able to establish undeniably in this way that the principal sign i- 
ficance of i n-b reeding is no thing else but the ge¬ 
neral probability of the meeting of similar pro¬ 
perties. The presence of similar properties leads, 
in all the cases both of i n-b reeding and eros s-b r e ed- 
i n g, to similar results. — By the term cross-breeding we 
understand the matings between non-related, or, more precisely, distantly- 
related specimens, also matings between specimens which possess different 
properties. The blood-relationship, however, from the inter se matings of 
full brothers and sisters, or the union between offspring and parents, re¬ 
presents a gradation up to the limit of the possibility of fertilization ; on 
the other hand, closely-related specimens exhibit sometimes different, 
and distantly-related specimens, similat 1 properties. The definition con¬ 
sequently cannot be upheld. Between in-breeding and cross-breeding 
no hard and fast line can be traced, the difference being only relati v e, 
viz., through I n-b reeding the properties become fixed, and under 
the influence of selection, natural or artificial, the properties of the produce 
can be made deviate gradually from the average, i. e., from the properties 
of the ancestral breed ; in-breeding and selection, consequently, may call 
up new properties, new breeds ; through Gros s-b r e.e din g, on the 
other hand, new properties cannot be called up, but when specimens with 
different properties — which were however originally derived from an¬ 
cestors which possessed similar properties — are crossed, the prepon¬ 
derance of the common ancestral properties come out, or in other 
words, reversion is the necessary consequence of cross-breeding. Gros s- 
breeding attracts the breeds towards the ancesto r, 
and i n-b reeding repels them in the opposite di¬ 
rection. The constancy of natural conditions promotes the chances 
Annales Musei Nationalis Hungarici. XV. 
47 
