Of course, Lu Chuan only gave a rough explanation.
The specific operation is much more detailed.
The ability to judge the time of death by judging the length of maggots at a glance is mostly written in the script.
In fact, in forensic entomology, judging the time of death of a corpse through the growth cycle of corpse parasites requires the assistance of many experiments.
Wang Changjiang was a little confused after hearing Lu Chuan's explanation.
With his knowledge base as a professional forensic doctor, he could certainly understand what Lu Chuan was talking about.
But just because I can understand it, I am confused.
Isn't Lu Chuan a current detective?
When did forensic entomology, a relatively unknown profession even among forensic medicine, still have an understanding of it?
He understands skeletal identification and analysis, and now he seems to have some understanding of forensic entomology.
What did this guy study when he went to college?
Behind the gas mask, Shen Yan's expression was very calm.
Lu Chuan once told her that he had some knowledge of forensic entomology.
Although Liu Guodong didn't know that Lu Chuan also had some research on forensic entomology.
But in terms of on-site investigation, fingerprint identification analysis, skeleton identification analysis, etc., Lu Chuan has shown enough.
Now that there is one more item, it seems that nothing is impossible.
Ahem.
Liu Guodong coughed lightly: "That's it. I'll go back and do experiments first. Yang Sen and Lao Bai haven't come out with the identification tests on the sharp knives yet. I'll go over and take a look."
"Xiao Lu, there's nothing big going on over there. You can help Forensic Doctor Wang determine the time of death of the body."
Liu Guodong took the clothes and left.
"What needs to be done next?"
As the chief forensic surgeon in charge of the autopsy, Shen Yan first sought Lu Chuan's opinion before performing the surgery herself.
"I need to collect a sufficient amount of larvae, as well as some skin and internal organ fragments on the surface of the corpse."
"It's best to use the liver and eyelids. If it can still be extracted, it's best to get some."
Any insect eggs that parasitize on corpses are overwhelmingly corpse flies.
The larvae of these corpse flies, just after hatching, have no teeth or other means of attack.
Therefore, corpse flies will choose to lay their eggs in the softest places.
On the surface of the corpse, the first places where parasite eggs are found are the eyelids, nasal mucosa, oral mucosa and other areas.
Inside the corpse, the liver is the fattest and most tender part, and it is also the first to be parasitized and later put to decay.
Shen Yan nodded. Lu Chuan was obviously not good at these specific operations, and she, a professional forensic doctor, needed to do them.
The two of them were working and chatting.
"When I was in college, I learned that corpse fly eggs begin to hatch after two or three days of parasitism, right?"
Although Shen Yan has not done much research on forensic entomology, she does have basic knowledge reserves. Not only that, but it is sufficient.
Lu Chuan nodded in affirmation: "In most cases, this is the case, but the most important thing is to look at the outside temperature and humidity."
"The hatching of corpse fly eggs will only begin when the temperature is above 15 degrees Celsius, and the maximum hatching temperature cannot exceed 40 degrees Celsius."
"If the weather is colder, the hatching period can be delayed by about a month at most."
"If the outside temperature is around 35 degrees Celsius, this cycle will be shortened to one day. Even if the humidity is also relatively suitable, the incubation time can be shortened to about twelve hours at the shortest."
Lu Chuan put a dozen white and fat larvae of different sizes into the bottle, lifted them up and looked at them. Each one was abnormally fat and squirming crazily at the bottom of the bottle.
Apparently, judging by the size of the larvae, the hatching times of these eggs are not synchronized.
Shen Yan nodded. She could not remember these things clearly. Maybe she had learned them but forgotten them, or maybe she had never learned them at all.
"I remember the book said that the average corpse fly's emergence cycle is about a week?
"
"Well," Lu Chuan continued to put the larvae that Shen Yan had stripped off the body into the bottle: "But the time of death of the body cannot be determined based on this."
Because what Lu Chuan needs to do now is to find out the largest and smallest among them, and judge their intergenerational relationship.
"The largest larvae on the corpses are not necessarily the offspring of the first batch of flies that laid eggs."
"It's very likely that it's the second generation, or even the third generation."
If it is determined to be the first generation, then the body should have decomposed in about a week.
This also depends on the external environment where the body is located, but it will most likely not exceed two weeks.
However, the weather in Haizhou City in April has recently become warmer, but it is not very hot.
At least it has not yet reached the optimal incubation temperature for corpse fly eggs.
Bodies will not decay quickly in this environment.
But considering the degree of decomposition of the corpse, it doesn't look like it could become like this in a week or two. .
Therefore, corpse fly eggs may not be the first generation, but may be the second or even third generation.
"The possibility of the fourth generation is very small. If the corpse fly has developed to the fourth generation, then the eggs will take at least a month to hatch."
Lu Chuan picked up a very small larvae, only about three millimeters: "The weather in Haizhou City is relatively cold in three months, the decay of corpses will not be so serious, and the corpse flies that breed will not be passed on from generation to generation so quickly."
The two of them were chatting, and Wang Changjiang was listening quietly without interrupting. He was probably more interested in what they were talking about.
However, as the most experienced forensic doctor in Haizhou City, it always feels a bit embarrassing to ask a newly recruited detective on forensic issues, or to learn secretly.
Therefore, Wang Changjiang simply stopped talking. Anyway, his task today was to record.
Shen Yan came from a major and has been working for more than two years. She has rich work experience and theoretical knowledge.
Dissecting a corpse is a piece of cake.
"Actually, maggot larvae are not all harmful. I read a document last year that talked about using fruit fly larvae to suck carrion to accelerate the rapid healing of rotten wounds."
The selection of larvae on the surface of the corpse was almost finished, and Shen Yan was ready to start the dissection.
"There is such a treatment method, but it is mostly used clinically abroad. In China, well, it is still used relatively rarely."
"The main reason is the lack of talents in this field."
Raising fruit fly larvae is not a particularly complicated matter.
The key is how to perform sterile culture.
Otherwise, if you use fruit fly larvae that breed from random carrion to treat decayed wounds, it is estimated that new infections will appear before the old wounds heal.
But in a sterile environment, corruption will stop, and fruit fly larvae will naturally not be able to hatch and grow.
This seems to be a fundamentally paradoxical subject.
But Lu Chuan knew that it was possible to cultivate in a sterile environment. He had this knowledge in the intermediate-level corpse parasite egg identification analysis he accepted.
