I used a common 1N4148 diode IV plot simulation, it used a 1K resistor.

I replaced the diode with 1N34 Germanium model I found but am not certain that this model is ok?
I was curious what the IV characteristics might look like around 300mV by setting the resistance to 300kΩ
From (2 nA, 300mV) the line curves and greater than (400nA, 575mV) the line is linear.
A screenshot of simulation and asc below:

 

The resistor controls the load line. It should not affect the I-V curve of the diode.

The I-V curve shown appears to be right for 1N34 germanium diode.

 

Below are the IV plots for a 1N4148 silicon diode (yellow trace) a 1N34 germanium diode (green trace), and a BAT54 Schottky diode (red trace), shown with a log current scale which gives a straight line, indicating the diodes' log response, over much of the sim test current range:

 

Here are Motorola models for 1N34 and 1N34A.

 

Mr. Chips, Crutschow, EEtech00. Load line, diode comparison another 1N34A and thermal will be helpful in
comparing and checking using practical values that could be measured on test bench, Thank you for the info.

.MODEL BAT85 D(IS=207.6n RS=2.326 N=1.023 CJO=12.1p EG=0.69 BV=33 IBV= 10u
.MODEL BAT54 D(IS=649n RS=2.09 N=1.04 CJO=12.4p EG=0.58 BV=50 IBV=100u

Probably would need a Faraday shield if building the real circuit. Metal cookie box maybe.